Electrical wiring is characterized by the method of laying, the minimum permissible cross-section, the permissible current load. Wiring methods are regulated by the Electrical Installation Rules (PUE) and GOST R 50571.15-97 (IEC 364-5-52-93) “Electrical installations of buildings. Part 5. Selection and installation of electrical equipment. Chapter 52. Wiring ".

The standard contains a number of requirements and provisions that differ significantly from the requirements of the PUE, which were in force at the time of the publication of the standard.

The requirements of the standard related to the features of wiring in office buildings are given below.

1. Insulated wires are allowed to be laid only in pipes, ducts and on insulators. It is not allowed to lay insulated wires hidden under plaster, in concrete, in masonry, in voids of building structures, as well as openly on the surface of walls and ceilings, on trays, on cables and other structures. In this case, sheathed insulated conductors or cables must be used.

2. In single- or three-phase networks, the cross-section of the neutral working conductor and the PEN-conductor (combined zero working and protective conductors) must be equal to the cross-section of the phase conductor with its cross section of 16 mm2 and below for conductors with a copper core.

With large cross-sections of phase conductors, it is allowed to reduce the cross-section of the neutral working conductor under the following conditions:

the expected maximum operating current in the neutral conductor does not exceed its continuous permissible current;

the protective neutral conductor is protected against overcurrent.

At the same time, the standard makes a special note regarding the current in the neutral working conductor: the neutral conductor may have a smaller cross-section compared to the section of the phase conductors if the expected maximum current, including harmonics, if any, in the neutral conductor during normal operation does not exceed the permissible load by current for a reduced cross-section of the neutral conductor.

This requirement should be associated with the fact of the flow of the 3rd harmonic of the current in the neutral conductor of three-phase networks with impulse power supplies (computers, telecommunications equipment, etc.) as part of the loads.

The value of the effective value of the current in the neutral working conductor at such loads can reach 1.7 of the effective value of the current in the phase conductors.

From 06.10.1999, new editions of section. 6 "Electric lighting" and 7 "Electrical equipment of special installations" of the seventh edition of the PUE. The content of these sections has been brought in line with the IEC set of standards for electrical installations of buildings.

In a number of separate clauses of the new edition of Sec. 6 and 7 PUE impose even more stringent requirements than in the standard based on IEC materials. These sections have been issued as a separate brochure "Electrical Installation Rules" (7th ed. - M .: NTs ENAS, 1999).

The seventh section of the PUE contains Ch. 7.1 deserves special attention. The chapter is called "Electrical installations of residential, public, administrative and residential buildings" and applies to electrical installations:

residential buildings listed in SNiP 2.08.01-89 "Residential buildings";

public buildings listed in SNiP 2.08.02-89 " Public buildings and structures "(with the exception of buildings and premises listed in Chapter 7.2);

administrative and utility buildings listed in SNiP 2.09.04-87 "Administrative and utility buildings".

Electrical installations of unique and other special buildings that are not included in the above list may be subject to Additional requirements.

Chapter 7.1 contains requirements for wiring and cable lines. When choosing the method of laying and sections of electrical wiring, guided by both the requirements of GOST R 50571.15-97 and the PUE, it should be borne in mind that the new edition of the PUE in part of clause 7.1.37 is formulated as follows: “... the electrical wiring in the premises should be carried out replaceable: hidden - in the channels of building structures, monolithic pipes; openly - in electrical skirting boards, boxes, etc.

In technical floors, underground ... electrical wiring is recommended to be carried out openly ... In buildings with building structures made of non-combustible materials, it is allowed to install permanently monolithic group networks in the grooves of walls, partitions, ceilings, under plaster, in the floor preparation layer or in voids building structures, carried out with a cable or insulated wires in a protective sheath.

The use of permanent, monolithic laying of wires in panels of walls, partitions and ceilings, made during their manufacture at factories of the building industry or carried out in the assembly joints of panels during the installation of buildings, is not allowed. "

In addition (clause 7.1.38 of the PUE), electrical networks laid behind impassable suspended ceilings and in partitions are considered as hidden electrical wiring, and they should be performed:

behind ceilings and in voids of partitions made of combustible materials in metal pipes with localization ability, and in closed boxes;

behind ceilings and in partitions made of non-combustible materials, in pipes and boxes made of non-combustible materials, as well as flame-retardant cables. In this case, the possibility of replacing wires and cables must be ensured. Non-combustible suspended ceilings are understood to be those that are made of non-combustible materials, while other building structures located above the suspended ceilings, including intermediate floors, are also made of non-combustible materials.

Appendix 3 provides an excerpt from GOST R 50571.15-97 with examples of electrical wiring in relation to office buildings. These illustrations do not provide an accurate description of the product or installation practice, but rather describe the installation method.

To carry out the wiring of the uninterruptible power supply network, it is necessary to use wires and cables with only copper conductors. The use of solid cables and wires is recommended.

The use of flexible multi-wire cables is possible on the network sections that are being reconstructed during operation or for connecting separate power consumers.

All connections must be made with branch clamps or spring terminals, while stranded conductors must be crimped using special equipment.

Due to the fact that the cross-section of the neutral working conductor must be designed for a current that can exceed the phase current by 1.7 times, and the existing nomenclature of wires and cables does not always allow to unambiguously solve this problem, it is possible to perform three-phase electrical wiring in the following ways:

1. When laying with wires, the section of the phase and protective conductors is made with one section, and the zero working (neutral) conductor is made with a section designed for a current that is 1.7 times greater than the phase one.

2. When laying with cables, there are three options:

when using three-core cables, the cable cores are used as phase conductors, the neutral working conductor is made with a wire (or several wires) with a cross-section designed for a current 1.7 times greater than the phase one, zero protective

Wire with a cross-section in accordance with clause 7.1.45 of the PUE, but not less than 50% of the cross-section of the phase conductors; instead of wires, it is possible to use cables with the appropriate number of cores and cross-section;

when using four-core cables: three cores are phase conductors, the neutral working conductor is also one of the cable cores, and the neutral protective conductor is a separate wire. In this case, it is determined by the operating current in the zero working conductor, and the cross-section of the phase conductors turns out to be overestimated (such a solution is the best from a technical point of view, but more expensive than others and is not always feasible at high currents);

when using five-core cables with cores of the same cross-section: three cores - phase conductors, two combined cable cores are used as a neutral working conductor, and a separate wire for a zero protective conductor. In this case, the cross-section of the cable is determined by the phase current (this solution is also the best from a technical point of view, but rather expensive; there are also difficulties in order to fulfill the government order, as well as with the supply of cables).

At high powers, it is possible to lay phase, neutral working and protective conductors with two or more parallel cables or wires. All cables and wires belonging to the same line must be laid along the same route.

Laying a neutral protective conductor for information and computer technology and electrical equipment must comply with the requirements of GOST R 50571.10-96 "Grounding devices and protective conductors", GOST R 50571.21-2000 "Grounding devices and potential equalization systems in electrical installations containing information processing equipment" and GOST R 50571.22-2000 "Grounding of information processing equipment".

Sourse of information:"Power supply of computer and telecommunication systems" Author: A. Yu. Vorobiev is a well-known specialist in the field of uninterrupted and guaranteed power supply systems. He supervised the creation and operation of large uninterruptible power supply systems of the Central Bank of the Russian Federation in Moscow and other regions of Russia. Author of power supply projects for intelligent buildings of YUKOS, LUKOIL, AEROFLOT, RF Ministry of Railways and a number of others. Author of many publications on the quality of electrical energy, structures and principles of construction of modern power supply systems.

GOST R 50571.15-97
ELECTRICAL WIRING
Electrical installations of buildings. Part 5.
Selection and erection of electrical equipment.
Chapter 52.
Wiring systems
OKS 27.020; 29.020
OKSTU 3402
Date of introduction 1997-07-01
Foreword
1 DEVELOPED by JSC "Elektromontazh"
2 INTRODUCED by the Technical Committee for Standardization TC 337 "Electrical equipment of residential and public buildings"
3 APPROVED AND PUT INTO EFFECT by the Resolution of the State Standard of Russia dated April 8, 1997 No. 125
4 This standard contains the complete authentic text international standard IEC 364-5-52 (1993) Electrical installations of buildings. Part 5. Selection and installation of electrical equipment. Chapter 52. Electrical Wiring "except for the one highlighted in italics in clauses 522.1.1, 522.6.2, 522.7.1, 522.12.2. The original text of IEC 364-5-52-93 replaced in these clauses is given in Annex A to this standard.
The standard also contains additional requirements in italics in clauses 521.1 (note and text in table 52 P), 521.3 (for schemes 11, 11A, 12-17, 21, 31, 31A, 32, 32A, 51, 52, in table 52H ), 522 (note 2), 525, 526.2, 527.1.1, 527.1.5, 527.2.4, 528.1.1
5 INTRODUCED FOR THE FIRST TIME
Introduction
This standard is part of a set of state standards for electrical installations of buildings, developed on the basis of the international standard IEC 364 "Electrical installations of buildings".
The numbering system of clauses and clauses in this standard corresponds to that established in IEC 364-5-52-93, therefore, in this standard, in the designation, for example, clause 521.1, number 5 denotes the part number of the international standard IEC 364-5-52-93, numbers 52 - chapter number, 521 - standard section number.
The use of the numbering system established by the IEC provides mutual coordination of the requirements of private standards of a set of state standards for electrical installations of buildings (GOST R 50571).
The requirements of this standard should be taken into account in the development and revision of standards, norms and rules for the device, testing, certification and operation of electrical installations of buildings.
The requirements regulated by the standard are determined by the type of wire or cable used, the method of their installation, laying, external influencing factors, the conditions for limiting the spread of combustion, approaching others engineering networks and structures, as well as the conditions for ensuring Maintenance.
The scope of the standard is in accordance with GOST 50571.1 (part 1, section 1).
Due to the significant differences between the requirements for external influencing factors (WWF), adopted in Russia and the CIS, from the requirements of IEC and ISO standards, this standard additionally, and in a number of clauses and instead of the requirements of IEC 364-5-52-93 includes the requirements of domestic and interstate (CIS countries) standards.
All amendments and additions to the text of the standard are highlighted in italics, and the corresponding authentic text is given in Appendix A to this standard. Appendix B contains the main provisions for checking the resistance of the mounted electrical wiring to the effects of special environments.
The standard contains a number of requirements and provisions that differ significantly from the requirements of the current Electrical Installation Rules (PUE). The most important of these are:
1 Insulated wires are allowed to be laid only in pipes, ducts and on insulators. It is not allowed to lay insulated wires hidden under plaster, in concrete, in brickwork, in voids of building structures, as well as openly on the surface of walls and ceilings, on trays, on cables and other structures. In this case, sheathed insulated conductors or cables must be used.
2 In single- or three-phase networks, the cross-section of the neutral working conductor and the PEN-conductor must be equal to the cross-section of the phase conductor with its cross-section of 16 mm and below for conductors with a copper core and 25 mm and below for conductors with an aluminum core. With large cross-sections of phase conductors, it is allowed to reduce the cross-section of the neutral working conductor, provided that:
- the expected maximum operating current in the neutral conductor does not exceed its long-term permissible current;
- the protective neutral conductor is protected against overcurrent.
3 It is not recommended to use soldering when connecting conductors of power circuits.
4 The requirements for sealing the places of passage of electrical wiring through walls and interfloor ceilings are increasing.
The introduced requirements increase the operational reliability, electrical and fire safety of electrical installations in buildings.
Prior to bringing the PUE into compliance with the IEC set of standards for electrical installations of buildings, PUE is applied in terms of requirements that do not contradict the specified set of standards.
1 AREA OF USE
This standard specifies the requirements for the selection, installation and operation of electrical wiring.
The standard applies to electrical installations of power, lighting and secondary circuits with voltages up to 1000 V AC and 1200 V direct current carried out inside buildings and structures, as well as on their outer walls and in the immediate vicinity of them using insulated wires and cables (GOST R 50571.1).

Measure the insulation resistance of the cable CORRECTLY. Measurement of electrical insulation resistance RISO up to 40 TΩ; Selection of measuring voltage in the range from 50 V to 10 kV; Automatic discharge of the capacity of the investigated object after completion of the measurement of the resistance of electrical insulation; Automatic calculation of absorption and polarization coefficients (degree of moisture and aging of insulation) AB1, AB2, DAR, PI; Measuring current - 1.2 mA, 3 mA or 5 mA; Two- and three-wire method for measuring electrical insulation resistance using conductors up to 20 m long; Support for AutoISO-5000 adapter with voltage up to 5 kV; Measurement of capacitance in the process of measuring the resistance of electrical insulation; Measurement of electrical insulation resistance with rising step voltage (SV); Measurement of the coefficient of discharge of dielectrics (DD); Localization of damage (burn-through).

2 REFERENCES
This standard uses references from the following standards:
GOST 9.005-72 ESZKS. Metals, alloys, metallic and non-metallic inorganic coatings. Permitted and unacceptable contact with metals and non-metals
GOST 9.303-84 ESZKS. Metallic and non-metallic inorganic coatings. General requirements for selection
GOST 12.1.004-91 SSBT. Fire safety. General requirements
GOST 12.1.010-76 SSBT. Explosion safety. General requirements
GOST 12.2.007.0-75 SSBT. Electrical products. General safety requirements
GOST 12176-89 Cables, wires and cords. Flame Retardation Test Methods
GOST 14254-96 Degrees of protection provided by enclosures (IP code)
GOST 15150-69 Machines, devices and other technical products. Versions for different climatic regions. Categories, operating conditions, storage and transportation in terms of the impact of climatic environmental factors
GOST 15543.1-89 Electrical products. General requirements in terms of resistance to climatic external Inactive factors
GOST 15963-79 Electrical products for areas with a tropical climate. General technical requirements and test methods
GOST 17516.1-90 Electrical products. General requirements in terms of resistance to mechanical external factors
GOST 24682-81 Electrical products. General technical requirements in terms of exposure to special environments
GOST 24683-81 Electrical products. Methods for monitoring resistance to the effects of special environments
GOST 28668.1-91 Low-voltage complete distribution and control devices. Part 2. Particular requirements for busbar systems (busbars)
GOST R 50462-92 Identification of conductors by colors or numbers
GOST R 50571.1-93 Electrical installations of buildings. Basic Provisions
GOST R 50571.2-94 Electrical installations of buildings. Part 3. Main characteristics
GOST R 50571.8-94 Electrical installations of buildings. Part 4. Security requirements. General requirements for the application of protective measures to ensure safety. Requirements for the application of measures of protection against electric shock
GOST R IEC 449-96 Electrical installations of buildings. Voltage ranges
52 GENERAL
52.1 When choosing and installing electrical wiring, the requirements of GOST R 50571.1 for cables and wires for their termination and / or connection, for their supporting or suspended structures, protective sheaths and methods of protection against external influences must be taken into account, as well as general safety requirements in accordance with GOST 50571.1 ( part 2).
Note - The requirements of this standard, in general, also apply to protective conductors, while in the corresponding private standards of the set of standards GOST 50571 additional requirements are established for protective conductors.
521 Types of electrical wiring
521.1 The method of wiring installation, depending on the type of wire or cable used, must be selected in accordance with table 52F, provided that the external influences on the wires or cables comply with the requirements of the current standards for these wires and cables.
521.2 The method of wiring installation, depending on the installation location, must comply with table 52G.
521.3 Examples of electrical wiring are shown in table 52H.
NOTE - Other types of electrical wiring, not provided for in this standard, can be used only provided that they meet general requirements of this standard.
521.4 Busbars
Busbars must meet the requirements of GOST 28668.1 and be mounted according to the manufacturer's instructions. In this case, installation work is carried out in strict accordance with the requirements of Sections 522 (except for paragraphs 522.1.1, 522.3.3, 522.8.1.6, 522.8.1.7 and 522.8.1.8), 525-528.
521.5 AC circuits Conductors enclosed in ferromagnetic sheaths shall be laid in such a way that all wires of each circuit are in the same sheath.
NOTE - If this condition is not met, overheating of the wires and significant voltage losses may occur due to the effect of inductance.

Table 52F - Wiring Selection

Wires and cables		Mounting method
		without fastening		in pipes	in boxes	in special boxes	on patches and brackets	on insulators	on a cable (string)
Bare wires		-	-	-	-	-	-	-	-
Insulated wires		-	-	+	+	+	-	+	-
Sheathed insulated wires and sheathed cables (including armored and mine-	Stranded	+	+	+	+	+	+	0	+
insulation)	Single-core	0	+	+	+	+	+	0	+

Legend:
"+" - allowed;
"-" - not allowed;
Note - Special box - a box of rectangular cross-section, designed for laying wires and cables, which does not have removable or opening covers.

Table 52G- Installation of wiring systems

Place of laying		Mounting method
		without fastening	direct mount	in pipes	in boxes	in special boxes	on patches and brackets	on insulators	on a cable (string)
In the voids of building structures	21, 25, 73, 74	0	22, 73, 74	-	23	12-16	-	-
In cable ducts	43	43	41, 42	31, 32	4, 23	12-16	-	-
In the ground	62, 63	0	61	-	61	0	-	-
In building structures	52, 53	51	1, 2, 5	33	24	0	-	-
Open laying on building structures	-	11	3	31, 32, 71, 72	4	12-16	18	-
In the air	-	-	0	34	-	12-16	18	17
In water	81	81	0	-	0	0	-	-

Designations: "+" - allowed;
Legend:
"+" - allowed;
"-" - not allowed;
"0" - not used or usually not used in practice.
Notes (edit)
1 digits in the table indicate the reference number (see table 52H)
Table 52G - Installation of electrical wiring systems
2 Values ​​of permissible current loads - according to GOST R 50571 (IEC 364-5-523).
Table 52H - Installation examples
NOTE The illustrations do not accurately describe the product or installation practice, but rather describe the installation method. ; >

Example	Description	Reference number
	Insulated wires in pipes embedded in walls	1
	Multicore cables in pipes embedded in walls	2
		3
		3A
		4
-	Single or multi-core cables in special ducts on the walls	4A
		5
		5A
-	Sheathed insulated wires, sheathed cables and / or armored cables, single or multi-core:
		11
		11A
		12
		13
	- on brackets, fixed horizontally or vertically	14
		15
		16
	Sheathed insulated wires, sheathed cables, single or multi-core, suspended on a cable (string) or having a supporting cable (string)	17
		18
	Sheathed insulated wires, sheathed cables, single or multi-core in the voids of building structures	21
		22
	Single or multicore cables in pipes in the voids of building structures	22A
		23
	Single or multicore cables in special boxes in the voids of building structures	23A
		24
	Single or multicore cables in special boxes in masonry	24A
-	Sheathed single or multicore cables:	-
	- laid in the voids of the ceiling - in double floors	-
-	Insulated wires, single or multi-core cables in boxes on the wall:	-
		31, 31A
		32, 32A
	Insulated wires in ducts recessed flush into walls or floors	33
	Single or stranded cables in ducts flush-mounted into walls or floors	33A
		34
-	Single or multicore cables in suspended boxes	34A
	Insulated wires in pipes laid in horizontal or vertical closed cable ducts	41
		42
	Sheathed cables, single or multi-core, in horizontal or vertical open or ventilated cable ducts	43
	Sheathed insulated wires, sheathed cables, multicore, embedded directly into walls	51
-	Sheathed insulated wires, sheathed cables, single or multi-core, embedded directly into the masonry:	-
		-
		53
	Sheathed cables, single or multi-core in pipes or in special ducts in the ground	61
	Sheathed cables, single or stranded in the ground:	62
		-
		63
		71
	Insulated wires and cables in skirting boxes * Space for communication cables and computer networks	72
-	Insulated conductors in pipes or sheathed cables, single or stranded, laid:	73
		-
		74
	Sheathed cables, single or multi-core, laid in water	81

521.6 Wiring in pipes and ducts
It is allowed to lay several circuits in the same pipe or duct, provided that all wires are insulated for the highest rated voltage of the circuits laid in this pipe or duct.
522 Selection and installation of electrical wiring depending on external influences
Notes (edit)
1 This section considers only those of the external influences specified in GOST R 50571.2, which significantly affect the wiring.
2 Specific operating conditions for electrical wiring in terms of the impact of external climatic factors (VVF) are established in accordance with GOST 15150 and GOST 15543.1 in accordance with one of the types of climatic modification specified in 321 GOST R 50571.2.
522.1 Temperature environment(321.1 GOST R 50571.2)
522.1.1 The selection and installation of electrical wiring must be made in such a way that it is suitable for operation at the highest local value of the ambient temperature in accordance with 5.4 and 5.5 of GOST 15150.
In this case, the upper and lower temperatures during the operation of the wiring must be set in accordance with Appendix 4 of GOST 15543.1.
522.1.2 Various components of the wiring, including cables and all accessories, should be mounted only at those temperatures that are specified in the relevant standards for specific types of products or given by the manufacturer in accordance with 1.3 of Appendix 4 of GOST 15543.1.
522.2 External heat sources
522.2.1 To protect electrical wiring from heating by external heat sources, one of the following or other equally effective methods should be used:
- shielding;
- removal of electrical wiring from heat sources at a sufficient distance;
- the choice of wiring, taking into account the additional temperature rise that may occur;
- local reinforcement of insulation or replacement of insulation material. If it is not possible to eliminate additional heating by the above methods, correction factors are applied for the temperature of soil, water or air, taking into account section 3 of Appendix 3 of GOST 15543.1.
NOTE Heat from external sources can be transferred by radiation, convection or heat conduction:
- from hot water supply systems;
- from devices and lamps;
- as a result of the technological process;
- through heat-conducting materials;
- from radiation from the sun or the environment.
522.3 Availability of water (321.4 GOST R 50571.2)
522.3.1 Electrical wiring should be selected and installed so that water ingress into them will not cause damage. The assembled wiring must have an IP degree of protection corresponding to its location.
Notes (edit)
1 In principle, undamaged cable sheaths and insulation in fixed installations can be regarded as sufficient protection against moisture penetration. Special consideration should be given to cables subject to frequent splashing, flooding or immersion in water.
2 Damage to electrical wiring should be understood as electrical breakdown of insulation and mechanical damage to its shells or insulation.
522.3.2 Provision should be made for the removal of water or condensation where it may accumulate.
522.3.3 Where electrical wiring can be exposed to waves (AD6), its protection from mechanical damage must be provided by one or more of the methods provided for in paragraphs 522.6, 522.7 and 522.8.
522.4 The presence of external solids (321.5 GOST R 50571.2)
522.4.1 Electrical wiring should be selected and installed in such a way as to minimize the hazards arising from the ingress of foreign solid particles. The assembled wiring must have an IP degree of protection corresponding to its location.
522.4.2 In the presence of a significant amount of dust (AE4), additional measures should be taken to prevent the accumulation of dust or other particles in quantities that can adversely affect the processes of heat removal from electrical wiring.
NOTE A type of wiring may be required to facilitate dust extraction (see clause 529).
522.5 Exposure to corrosive and polluting substances (321.6 GOST R 50571.2)
522.5.1 Where the presence of corrosive or polluting substances, including water, can cause corrosion or deterioration of the electrical wiring, its parts that can be damaged should be appropriately protected or made of materials resistant to such substances.
NOTE Acceptable means of additional protection during installation work can be protective tapes, paints or lubricants.
522.5.2 Dissimilar metal contact, which causes electrolytic processes, should be avoided unless special precautions are taken to prevent the consequences of such contact.
522.5.3 Materials liable to cause mutual or individual degradation of their quality should not be in contact with each other.
522.6 Impacts (321.7.1 GOST R 50571.2)
522.6.1 Select and install electrical wiring to minimize damage from external mechanical influences.
522.6.2 In stationary installations that can be subjected to shocks established for conditions M43 during operation, appropriate protection can be provided:
- the mechanical characteristics of the wiring, or
- the choice of its location, or
- by additional local or general mechanical protection, or
- a combination of the above methods.
522.7 Vibration (321.7.2 GOST R 50571.2)
522.7.1 Electrical wiring laid along the structures of equipment subject to vibration of medium or high severity (M5, M6, M43 GOST 17516.1) or attached to them must comply with these conditions. This is especially true for cables and their connections.
NOTE Particular attention should be paid to the connection of electrical wiring to vibrating equipment. For this, local measures such as flexible wiring can be applied.
522.8 Other mechanical influences
522.8.1 Wiring must be selected and installed in such a way that damage to the sheath and insulation of cables or insulated conductors, as well as their connections during installation and operation, is prevented.
522.8.1.1 For concealed electrical wiring in building structures, pipes or special cable ducts must be fully assembled for each circuit before insulated wires or cables are tightened in them.
522.8.1.2 The radius of bending of wires and cables shall be such that they do not damage them.
522.8.1.3 When laying wires and cables on supporting structures with a support at a certain distance, the latter must be such as to exclude damage to the wires and cables from their own weight.
522.8.1.4 For places where electrical wiring is subjected to constant (for example, tensile force on vertical sections of the route from its own weight), the appropriate type of cable or conductor of the required cross-section and installation method should be selected in order to avoid damage to the conductors and cables from their own weight.
522.8.1.5 Electrical wiring that involves pulling and pulling wires or cables must have appropriate access means to do so.
522.8.1.6 Wiring in floors shall be adequately protected to prevent damage during normal use of the floor.
522.8.1.7 Electrical wiring, rigidly fixed and embedded in the walls, should be located horizontally, vertically or parallel to the edges of the walls of the room.
Electrical wiring, laid in building structures without fastening, can be placed along the shortest path.
522.8.1.8 Flexible electrical wiring should be installed in such a way as to avoid exposure of wires and connections to excessive tensile forces.
522.9 Presence of flora and / or mold (321.8 GOST R 50571.2)
522.9.1 In places where such a hazard exists or may arise (AK2), an appropriate type of wiring should be selected or special protective measures should be taken.
NOTE It may be necessary to apply an installation method that will remove emerging vegetation or mold (see clause 529).
522.10 Presence of fauna (321.9 GOST R 50571.2)
522.10.1 For places where such a hazard exists or can be expected, it is necessary to choose the appropriate type of wiring or provide special protective measures, for example:
- selection of electrical wiring with appropriate mechanical characteristics, or
- selection of an appropriate location, or
- application of additional local or general mechanical protection, or
- a combination of the above methods.
522.11 Solar radiation (321.11A GOST R 50571.2)
522.11.1 In areas where significant solar radiation, you should choose the appropriate type of wiring for these conditions or provide the necessary shielding.
NOTE See also 522.2.1 for elevated temperature.
522.12 Impact of seismic factors (321.12 GOST R 50571.2)
522.12.1 When choosing and installing electrical wiring, one should take into account the seismic hazard of the installation location.
522.12.2 In places where there is a danger of seismic impact, special attention should be paid to:
- fastening the electrical wiring to the building structures of buildings, taking into account the mechanical effect on the electrical wiring at the most unfavorable (from seismic vibrations with accelerations according to Appendix 6 of GOST 17516.1) mutual displacements of building elements;
- connections of the fixed wiring to the main equipment. For example, for security systems, an appropriate degree of flexibility in wiring must be provided.
522.13 Air movement (321.14 GOST R 50571.2)
522.13.1 See paragraphs 522.7 and 522.8.
522.14 Building structure (SV1, SV2, SV3, SV4) (323.2 GOST R 50571.2)
522.14.1 Where building structures can move relative to one another (CB3), the fastening of wires and cables and their mechanical protection should allow such a relative displacement that does not expose the wires and cables to excessive mechanical stress.
522.14.2 Flexible wiring should be used in buildings with flexible or unstable structures (CB4).
NOTE See clauses 522.7, 522.8, 522.12.
523 Permissible current loads (GOST R 50571.2, IEC 364-5-523)
524 Conductor cross-sections
524.1 The cross-sections of phase conductors in AC circuits and current-carrying conductors in DC circuits shall not be less than the values ​​specified in table 52J.
524.2 The cross-section of the neutral conductor and the PEN conductor, if any, must be the same as that of the phase conductors:
- in single-phase two-wire circuits, regardless of the section;
- in multi- and single-phase three-wire circuits with a cross-section of phase conductors less than or equal to 16 mm for copper and 25 mm for aluminum conductors.
524.3 In multiphase circuits in which the cross-section of each phase conductor exceeds 16 mm 2 for copper and 25 mm 2 for aluminum conductors, the neutral conductor may have a smaller cross-section than the phase conductors, while the following conditions are met:
- the expected maximum current, including harmonics, if any, in the neutral conductor during normal operation does not exceed the value of the permissible current load for the reduced cross-section of the neutral conductor.
NOTE The load on the chain during all normal use should be practically evenly distributed between the phases;
- the neutral conductor is protected against overcurrents in accordance with the requirements of 473.3.2 GOST R 50571.8;
- the cross-section of the neutral working conductor and the PEN conductor is at least 16 mm for copper and 25 mm for aluminum conductors.

Table 52J- Minimum conductor cross-sections

Types of wiring		Purpose of the circuit	Conductor
		-	Material	Section, mm
	Cables and insulated conductors	Power and lighting circuits	Copper Aluminum	1.5 2.5 (see note 1)
Stationary electric			Copper	0.5 (see note 2)
installations	Bare conductors	Power circuits	Copper Aluminum	10 16
		Signaling and control circuits	Copper	4
Flexible connections with insulated		Internal installation in devices and devices		According to the norms and requirements of the relevant standards
conductors and cables		In other cases	Copper	0.75 (see note 3)
		In extra-low voltage circuits for special applications		0,75

Notes (edit)
1 Terminals used to terminate aluminum conductors shall be tested and designed for this purpose.
2 For signaling and control circuits intended for electronic equipment, the minimum allowable cross-sectional area of ​​conductors is 0.1 mm
3 Note 2 also applies to multicore flexible cables with seven or more conductors.
525 Voltage losses in electrical installations of buildings
Note - Voltage losses in electrical installations of buildings should not exceed 4% of the rated voltage of the installation. Temporary conditions such as transients and voltage fluctuations caused by incorrect (erroneous) switching are not taken into account.
526 Electrical connections
526.1 Connections of conductors to each other, as well as their connection to equipment, must ensure constant electrical conductivity of the circuit and adequate mechanical strength and protection.
526.2 When choosing a connection method, the following should be taken into account accordingly:
- conductor material and its insulation;
- the number and shape of the wires forming the conductor;
- conductor cross-section;
- the number of conductors that will be connected together;
- environmental conditions and areas of premises for explosion and fire hazard.
NOTE Soldering of power conductor connections should be avoided. However, if such connections are used, they should be made taking into account their possible displacements and mechanical effects (see paragraphs 522.6-522.8).
526.3 All connections shall be accessible for inspection, testing and maintenance, except for the following connections:
- connections of cables in the ground;
- joints filled with a compound or sealed;
- connections of cold ends with heating elements floor and ceiling heating systems.
526.4 Where necessary, care shall be taken to ensure that the temperature of the joints during normal operation does not impair the insulation of the conductors connected to or supporting them.
527 Selection and installation of electrical wiring according to the conditions for limiting the spread of combustion
527.1 Precautions within a separate room bounded by fire-rated building structures
527.1.1 The danger of combustion propagation can be reduced by choosing appropriate materials and installation methods in accordance with the requirements of GOST 12.1.004, GOST 12.2.007.0, GOST 12176 and the requirements set out in paragraph 522 of this standard.
527.1.2 Installation of electrical wiring should not reduce the performance of building structures and fire safety.
527.1.3 Cables and other wiring elements with the required fire resistance specified in the relevant standards can be used without any additional precautions.
Note - In electrical installations where there are special fire hazard conditions, it may be necessary to use special types of wires and cables.
527.1.4 The use of cables that do not meet at least the requirements of standards to limit their ability to spread combustion should be limited to small sections for connecting electrical appliances to permanent electrical wiring networks and in any case should not be allowed for laying between rooms separated by fireproof partitions.
527.1.5 Wiring elements, other than cables that do not at least meet the requirements of the relevant standards for the ability to propagate combustion, but in all other respects meet the requirements of the standards, must be completely enclosed in a sheath of non-combustible materials or protected (covered, painted) with non-combustible materials.
527.2 Sealing wiring ducts
527.2.1 When wiring passes through structural elements of buildings and structures, such as floors, walls, roofs, ceilings, partitions, the fire resistance of which is determined by the project, the remaining openings must be sealed with a degree of fire resistance equal to the fire resistance of the corresponding elements of building structures.
527.2.2 Wiring made in pipes, special ducts, ducts, busbars or tires that pass through structural elements of buildings that have an established fire resistance must have an internal seal that provides the same fire resistance as the corresponding elements of the building structure. Likewise, they must be sealed externally as required by clause 527.2.1.
527.2.3 The requirements of 527.2.1 and 527.2.2 are considered satisfactory if the wiring seal is type tested.
527.2.4 Wiring in pipes and ducts, in which materials are used that meet the requirements of the standard for the spread of fire and have a maximum internal section of 710 mm, it is allowed not to be sealed from the inside, provided that:
- the wiring has a degree of protection not lower than IP33;
- any termination of electrical wiring has a degree of protection not lower than IP33.
527.2.5 No electrical wiring may pass through the structural members of a building if the integrity of those structural members of the building cannot be ensured after the installation of the electrical wiring.
527.2.6 Seals made in accordance with the requirements of 527.2.1 and 527.2.3 shall meet the requirements of 527.3 and specified in the notes below.
Notes (edit)
1 These requirements can be attributed to material standards if such standards are developed:
- the materials used must be compatible with the wiring materials with which they are in contact;
- they must allow thermal movement of electrical wiring elements without compromising the quality of the seal;
- they must have adequate mechanical strength in order to withstand the stresses that may arise from damage to the supporting structures of the electrical wiring as a result of fire.
2 Compliance with the requirements of this subparagraph can be ensured if:
- the cable fixing or supporting structures are located within 750 mm of the sealing seal and are capable of withstanding the mechanical stresses expected in the event of a fire failure of the cable fasteners from the fire side, so that the seal does not experience additional stress;
- or the design of the sealing device itself provides the required strength.
527.3 External influences
527.3.1 Seals designed to meet the requirements of 527.2.1 and 572.2.2 shall withstand the external influences to the same extent as the wiring for which they are used and, in addition, they shall meet the following requirements:
- withstand the effects of combustion products with the same degree calculated for structural elements of buildings through which the electrical wiring passes;
- provide the same degree of protection against water penetration required from structural elements of buildings in which they are made;
- The wiring seal must be protected from water running down along the wiring or collecting around the seal, unless the materials used for the seal are water resistant.
527.4 Installation conditions
527.4.1 Wiring may require temporary seals.
527.4.2 When working on changing the electrical wiring, the seal should be restored as soon as possible.
527.5 Inspection and testing
527.5.1 Seals shall be checked to ensure that they are made in accordance with the installation instructions.
527.5.2 No further tests are required after this check.
528 Rapprochement with other engineering networks
528.1 Convergence to power grids
528.1.1 Electrical circuits with voltages of ranges I and II in accordance with GOST R IEC 449-96 should not be in the same wiring if each cable does not have insulation designed for the maximum voltage present in this wiring, or if at least one of the following conditions:
- each conductor of a multicore cable is insulated for the maximum voltage in the cable, or
- cables with insulation for different voltages are mounted in separate sections of special cable ducts or ducts, or - laying in different pipes is used.
NOTE Special consideration may be required for the potential effects of electromagnetic and electrostatic interference on communication lines, computer networks, and similar networks.
528.2 Proximity to non-electrical grids
528.2.1 Do not install electrical wiring near sources of heat, smoke or steam, which can be harmful to them, if they are not protected from such influence by appropriate shielding that prevents heat removal from them.
528.2.2 In places where wiring runs under networks that are prone to condensation (such as water, steam or gas networks), measures should be taken to protect the wiring from their harmful effects.
528.2.3 Where electrical networks are located adjacent to non-electrical networks, they must be located so that any intended operations on these networks would not harm the electrical networks and vice versa.
NOTE This can be achieved:
- placing networks at a sufficient distance from each other;
- using mechanical and thermal shielding.
528.2.4 Where electrical networks are located near other networks, the following conditions must be met:
- electrical wiring must be well protected from the harmful effects of other networks during normal operation;
- protection against indirect contact must be provided in accordance with the requirements of GOST R 50571.3, while non-electrical metal networks should be considered as third-party conductive parts.
529 Selection and installation for maintenance conditions, including cleaning
529.1 When choosing and installing electrical wiring, the knowledge and experience of the specialists who are expected to service this system should be taken into account.
529.2 If necessary, delete protective equipment during repair or maintenance, ensure that they are immediately restored to their original condition.
529.3 Provide safe and easy access to all electrical wiring that may require service or repair.
Note - In some cases, it is necessary to provide means of permanent access to electrical wiring in the form of stairs, bridges, etc.
APPENDIX A
(reference)
AUTHENTIC TEXT OF PARAMETERS (PARAMETERS) IEC 364-5-52-93, WHICH REQUIREMENTS ARE REFINED IN THIS STANDARD
The authentic text of clauses (paragraphs) of IEC 364-5-52-93, according to which the corresponding clauses of this standard were amended, are shown in Table A. 1.

Table A1

Section number, paragraph (paragraph)		Authentic IEC 364-5-52 text
of this standard	IEC 364-5-52
522.1.1	522.1.1	522.1.1 The selection and installation of electrical wiring are carried out taking into account the highest ambient temperatures. The temperature limit specified in Table 52A of IEC Publication 523 must not be exceeded (clauses and subclauses of IEC Publications 321 and IEC 323 are given in IEC 364-3)
522.6.2 (first paragraph)	522.6.2 (first paragraph)	522.6.2 In stationary installations, which may be subject to impacts of medium (AG2) or high (AG3) severity during operation, adequate protection can be provided
522.7.1 (first paragraph	522.7.1 (first paragraph)	522.7.1 Wiring suitable for or fixed to equipment subject to moderate (AH2) or high vibration (AH3) shall meet these conditions.
522.12.2	522.12.2	522.12.2 In places with low (AP2) or increased seismic hazard, special attention should be paid to: - fixing the electrical wiring to the structures of buildings; - connections of the fixed wiring with all nodes of the main equipment, i.e. ensuring the flexibility of these connections.

APPENDIX B
GUIDELINES FOR CHECKING THE RESISTANCE OF ELECTRICAL WIRING TO EXPOSURE TO SPECIAL ENVIRONMENTS
When preliminary checking the compliance of the resistance of electrical wiring with the requirements for operation in conditions of exposure to special environments (see 522.5), the following provisions apply:
B1 The assessment of the durability of electrical wiring is carried out at the stage of research and development or development work on the development of its typical units (which corresponds to acceptance or preliminary tests in accordance with GOST 16504).
B2 The durability of electrical wiring elements in accordance with 522.1.2 can be verified by tests in accordance with GOST 24683.
B3 If it is required to check the electrical wiring by testing according to the GOST 24683 modes, then the models or its individual critical units in full size are subjected to tests.
B4 The test of electrical wiring according to paragraph B3 is not carried out if the elements included in it meet the requirements of 522.5.1 and 522.5.2, and its design features are such that the connection of the elements into the system does not change the parameters of the elements or the wiring in general with respect to resistance to special environments ...
B5 It is allowed not to test the wiring according to paragraph B3, if the requirements of paragraphs B. 5.1 and B. 5.2 are met:
B. 5.1 Wiring is designed for operation in gas and vapor media of group 5 in accordance with GOST 24682 with effective values ​​of their concentration less than 0.4 MPC (and for SO2, H2SO4, CO2 - 0.8 MPC), while the durability of the wiring can be guaranteed the use of resistant materials and coatings in accordance with GOST 9.303.
B. 5.2 Exposure to special environments on electrical wiring under operating conditions will occur during half or less of its established service life.

Key words: electrical installations of buildings; selection of electrical equipment; installation of electrical equipment; electrical wiring; lighting and secondary networks; busbars; alternating current circuits; installation method; the wire; cable; permissible current loads; cross-sections of conductors; voltage losses; electrical connections; sealing of electrical wiring passages; convergence with power grids

Any owner of a private house or apartment sooner or later faces the need to repair, replace or install electrical wiring.

If it is decided to install the electrical wiring, it means that a major overhaul is outlined in the apartment. This task looks different when building a private house, when the markup has to be done from scratch. It is also important to consider all possible options laying of wires, each of them has its own rules and regulations.

ELECTRICAL WIRING TYPES

There are two ways to install electrical wiring:

• hidden;
• open.

The first option is practical, since communications are not visible on the walls, ceiling and floor. This method is used in concrete or brick houses.

In timber-frame buildings, the installation of an open-type electrical network is relevant. Hidden electrical wiring in wooden buildings is a risk of fire if installation rules are not followed or wiring malfunctions.

Installation of hidden electrical wiring is carried out along the walls, floor or ceiling.

The advantages of hidden wiring.

1. Does not spoil the interior of the premises and decorative finishes.

2. It is securely fixed in the walls and fully complies with the fire safety rules.

3. There is practically no risk of damage, except when repairs are being carried out.

4. All wiring elements serve for a long time.

In addition to the advantages of the closed method, there is a significant drawback - the complexity of finding a break and troubleshooting.

Advantages open way gaskets.

1. In the event of a malfunction, it is always easy to find the damaged area and remove the wire. This is a simple job that does not require much time and money.

2. Conveniently connect additional points and electrical wiring.

Of the minuses, a high risk of mechanical damage and sometimes not a very good appearance of the wiring can be noted, which may not fit well into the overall arrangement of the room.

GENERAL REQUIREMENTS

There are four points that are often ignored and therefore require close attention:

• convenient access to switching (distribution) devices;
• safe placement of switches;
• installation options for sockets;
• ways of laying cables and wires.

The locations of the sockets.

Modern standards do not strictly limit the height of the outlet. The main condition is ease of use and electrical safety.

Usually, there are several electrical appliances in a room, so it makes sense to install a different outlet for each one to avoid the use of extension cords and tees.

When placing sockets on building partitions between rooms, groups are often installed that are on opposite sides one wall. This saves money and installation time.

Installation of switches.

To illuminate the room, you need to provide an individual switch for each device. It is customary to install switches in a house or apartment in the same way for convenient control.

It makes sense to place them at the entrance to the room by the door. A typical height of 1.5 meters from the floor will be inconvenient for young children. This is especially important for children's rooms and toilets. It is rational to place switches at the level of an adult's lowered hand, which will be convenient for all residents.

INSTALLATION OF HIDDEN ELECTRICAL WIRING

The creation of an electrical network using this method is carried out in several stages.

Drawing up an installation diagram.

Laying hidden wiring begins with drawing up a diagram. It is required to think over the installation locations of sockets, switches, lamps, electrical panel and outline the wiring lines.

Drilling holes in the wall.

After drawing up the diagram, they begin to make holes with a diameter of 72 mm (this is the standard size for socket outlets) in the places where it is planned to install switches, sockets and a branch box. For this, a perforator or drill with a special crown for concrete is usually used.

Shtroblenie walls.

After drilling the holes along the marked lines, the electrical wiring is channeled through the wall. To do this, first, two parallel cuts are made in the wall with a special chasing cutter, then the concrete between them is knocked out with a perforator.

There is another way to perform this procedure, when an angle grinder is used instead of a wall chaser.

Cabling.

In the prepared grooves, you need to lay and fix the cable. This can be done either by tacking the cable with gypsum plaster, or using special brackets.

Installation of junction boxes.

Installation of electrical wiring at this stage consists in the fact that boxes are fixed in the prepared holes, into which switches and sockets will be installed in the future. Fastening is best done on gypsum plaster.

To fix the socket you need:

• clean the hole from dust, concrete chips and moisten the surface;
• put plaster into the hole;
• insert a socket into the hole, having previously prepared a hole in it for cable entry;
• after the plaster has dried, remove the excess with a spatula.

The final stage.

In conclusion, puttying of the grooves with a cable is performed, switches are installed in the mounting boxes lighting fixtures, sockets, assemble a wiring diagram by connecting wires in junction boxes.

OPEN WIRING

Installation of open wiring is carried out in several stages. Let's take a closer look at each of them.

Scheme development.

This stage is common when laying both open and closed electrical wiring in the house. You will need to think over the installation locations of sockets, switches, lamps, electrical panel and outline the wiring lines.

Installation of electrical equipment.

The most common surface wiring installation methods are in ducts and brackets. For convenience, installation begins with the installation of sockets, switches, junction boxes, electrical panel.

Installation of boxes and laying of cables.

After installing the equipment, proceed to the installation of the box along the planned lines of wiring. It comes in different sizes and colors, and usually has a standard length of 2 m. For installation, the box is cut into pieces of the required length.

It is mounted simply: you need to open the lid and screw the base of the box to the wall with screws or dowel-nails. Then the cable is laid in the box, and the structure is closed with a lid.

When installing electrical wiring on the brackets, sockets, switches, and an electrical panel are first installed. Then the cable is laid, which is attached to the wall with brackets.

Equipment connection.

After everything is mounted and the wiring is done, they begin to connect the electrical equipment and assemble the wiring diagram by connecting the wires in the junction boxes.

ELECTRICAL WIRING IN THE FLOOR

In some situations, floor wiring is carried out. Floor wiring is carried out subject to the following rules:

1. The cable is protected with a corrugation or a metal sleeve when installing the route under a concrete screed and a steel pipe when wiring the electrical network under a wooden floor.
2. No twists are allowed in the floor. All wires are located in junction boxes, which are installed under the floor covering.
3. When installing electrical wiring in the floor surface, the corrugation is filled up to 40% of the internal volume.
4. The maximum length of one track should not exceed 20 m.
5. When conducting wiring in a wooden floor, the tree must be treated with fire-fighting agents.
6. When laying electrical wiring in the floor, you must not make a branching route from the shield. In such a situation, it will be difficult to change the damaged section of the cable.
7. The thickness of the screed under the corrugation is at least 30 mm.

The installation procedure can be different: either first, a network of pipes is created into which the cable is threaded, or the installation of routes with the cable inside is immediately carried out.

The main thing to consider is that before pouring a concrete screed or stuffing a board on logs, you need to check the finished power grid for an open circuit or short circuit. Then you can start laying the floor, connecting sockets, switches, lamps.

SUMMARIZING

The document that thoroughly defines the rules and regulations for the installation of electrical wiring is the PUE (rules for electrical installations).

When installing electrical wiring, the following basic rules should be observed:

• all counters, boxes, switches, sockets must be located in easily accessible places so that, if repair (maintenance) is required, they have free access (all live parts of the elements must be closed);
• switches must be placed near front door or near the doorway, mounting height 1-1.5 meters. It is worth remembering that for the convenience of using the switches, they must be installed on one side (in the direction of travel) in all rooms;
• sockets are installed in the places where electrical equipment is supposed to be located, the height of their installation should not exceed 50-80 cm. Professional installation of electrical wiring involves installation at the rate of 6 sq. m. - one socket. Also, the rules provide for at least three sockets in the kitchen, excluding its area;
• in the toilet, bathroom, the installation of sockets is prohibited, but they can still be installed, only the connection of the elements must be carried out through an isolation transformer;
• the wire is laid only horizontally or vertically. Horizontal laying is carried out in compliance with the following dimensions: 150 mm from the ceiling, 50-100 mm from eaves or beams, 150-200 mm from the floor. Vertical - at a distance of 100 mm from corners and openings;
• cabling in bundles is prohibited, i.e. if there are several parallel wires, they should be placed at a distance of at least 3 mm from each other;
• all wire connections are made in special branch or junction boxes (the installation of electrical wiring for a wooden house also involves the use of special asbestos gaskets);
• neutral and grounding wires at the entry point are connected by welding. They are connected to electrical appliances with bolted (screw) connections.

When designing and installing electrical wiring, devices should be used that ensure the electrical and fire safety of the facility (circuit breakers, residual current devices - RCDs, grounding systems).

It is probably unnecessary to talk about the need to ensure a high-quality connection of wires, their reliable insulation, and compliance with the relevant safety rules during installation.

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During repairs in an apartment or house, the question usually arises of how to properly replace the electrical wiring. If you want to do it yourself, then you need to know all the subtleties. correct wiring.

As with other types of work, the installation of electrical wiring begins with planning, which is based on the principles of convenience and safety. Basically, of course, in developing a plan, the emphasis is on safety, because electricity is such a thing where negligence is unacceptable.

The work must be competent and neat, which will save you from problems and protect your home. A clear plan must be adhered to at all stages of work.

10 rules for wiring

Consider the main points taken into account in developing a plan.

No. 1. Sockets, electricity meters, as well as junction boxes should be installed in easily accessible places for maintenance and repair work.

No. 2. Conductive elements must be covered and insulated from strangers.

No. 8. Installation open cable routing(not to be confused with wire) wiring allowed in all areas for cooking and eating, except for kitchens in apartments. Those. open cable routing is prohibited in apartment kitchens. Installation and wiring in the form of open wiring in these rooms is prohibited. In apartment kitchens, the type of electrical wiring should (maybe) be the same as in living rooms.

Footnotes from the PUE to the open account:

No. 9. In rooms with high humidity, such as baths, saunas, showers, only hidden wiring or open cabling should be used.

Internal wiring is the indoor wiring.

Outside is the wiring laid along the outer walls of buildings and structures, under awnings, etc., as well as between buildings on supports (no more than four spans 25 m long) outside streets and roads. Open and hidden electrical wiring. According to the method of execution, the wiring can be open and hidden. Open wiring includes wiring laid on the surface of walls, ceilings, on supports, farms and other building elements of buildings and structures. In this case, wires and cables are laid directly on the surface of walls, ceilings, on rollers, insulators, on cables, on brackets, in pipes, in flexible metal sleeves or directly by gluing to the surface. Open wiring can be stationary, mobile and portable.

Open electrical wiring includes wiring laid inside structural elements of buildings and structures (in walls, floors, ceilings), as well as in plastered furrows, without furrows under a layer of wet plaster, in closed channels and voids of building structures, etc. Wires and cables are laid in this case either in pipes, flexible metal sleeves, boxes, or without them.

Concealed wiring completely protects wires and cables from mechanical damage and environmental influences.

Replaceable and non-replaceable electrical wiring. Hidden wiring can be replaceable and non-replaceable:

Replaceable is a wiring that allows the replacement of wires during operation without destroying building structures. In this case, the wires are laid in pipes or channels of building structures;

Irreplaceable wiring cannot be dismantled without destroying structures or plaster. The design of electrical wiring in a garden house, cottage or residential building begins with drawing an electrical connection diagram tied to the floor plan of the house on a scale of 1: 100 (1: 200).

The electrical wiring on the plan is applied in a single-line design. Luminaires, switches, plug sockets, protection devices on the plan drawings are designated with conventional symbols.

In fig. 1 a shows a diagram of the electrical wiring in a three-room room.

Rice. 1. Wiring diagrams: a - a diagram of a three-room room with electrical wiring; b - a diagram of the simultaneous switching on and off of lamps; c - a circuit with a switch for 4 positions; d - circuit with switching on and off lamps from two places; e - circuit for turning on and off lamps from more than two places: 1 - two wires of the line; 2 - apartment lighting panel; 3 - single-pole switch; 4 - plug socket; 5 - two-pole switch; 6 - three wires in a line; on - switch

In room I two electric bulbs are installed, which are simultaneously switched on and off by a general switch. A schematic diagram of the wiring in room I is shown in fig. 1 b.

In room II the switch is installed for four switches (Fig. 1 c). In the position of the switch shown in the diagram, both lamps are on. At the first turn to the right, both lamps will be off, at the second - lamp L1 is on, and at the third - lamp L2. The room has a plug socket.

In room III, having two entrances, four lamps are installed, which light up simultaneously (Fig. 1d), and two switches. By any of the switches, all lamps can be turned on or off.

In fig. 1 e shows a lighting scheme in which lamps can be turned on from more than two places.

On the floor plan with applied electrical wiring near the lines indicate the brand and section of the wire or cable, conventionally denote the method of laying, for example: T - in metal pipes, P - in plastic pipes, Mr - in flexible metal sleeves, I - on insulators, P - on rollers, Tc - on cables ... The number of wires, cores in the wire and their cross-sectional area are shown as a product. For example, the designation PV2 (1x2.5) is deciphered as follows: two single-core wires of the PV brand with a conductor cross-section of 2.5 mm 2. The number of wires in the amount of more than two is indicated by serifs at an angle of 45 ° to the line. For luminaires, the power of the lamp (W) is indicated in the numerator with a fraction, and the height of the suspension above the floor (m) in the denominator. The receiver of electrical energy is also referred to as a fraction. The numerator indicates the plan number and the denominator the rated power (kW). In various climatic zones of the country, a variety of building materials and structures are used in the construction of garden houses, cottages and summer cottages.

All erected buildings are divided into three categories:

By the degree of flammability of building materials and structures;

By environmental conditions;

By the degree of electric shock.

In accordance with the requirements of "Building codes and regulations" (SNiP 111-33-76), all building materials and structures are divided into three groups: combustible, hardly combustible and non-combustible.

The characteristic of the degree of flammability of materials and structures is given in tab. 1.

Table 1. Flammability of building materials and structures

Fireproof includes all natural and artificial inorganic materials used in construction; metals, gypsum and gypsum fiber boards with an organic matter content of up to 8% by weight; mineral wool boards on a synthetic, starch or bitumen bond with a content of up to 6% by weight.

Non-combustible materials include materials consisting of non-combustible and combustible components, for example, asphalt concrete, gypsum and concrete materials containing more than 8% by weight of organic aggregate; bituminous mineral wool slabs with a content of 7-15%; clay-straw materials with a density of at least 900 kg / m 3; wood, deeply impregnated with fire retardants, fiberboard, textolite, other polymeric materials.

Combustible includes all other organic materials.

The Electrical Installation Rules (PUE) adopted the following classification of premises for environmental conditions:

1. Dry: the relative humidity in them does not exceed 60% - these are residential heated premises.

2. Humid: relative humidity does not exceed 75%, vapors or condensing moisture are released only temporarily and, moreover, in small quantities (unheated rooms, canopy of residential buildings, warehouses, sheds, utility rooms, kitchens, etc.).

3. Raw: Relative humidity exceeds 75% for a long time.

4. Particularly moist: the relative humidity is close to 100%. The ceiling, walls, floor and objects in the room are covered with moisture (bathrooms, shower rooms, toilets, basements, vegetable stores, greenhouses, etc.).

5. Hot: the temperature exceeds 30 ° C for a long time (steam rooms, saunas, attics, etc.).

6. Dusty: they can generate abundant technological dust in such an amount that it can settle on the wires and penetrate into the electrical equipment.

7. Premises with a chemically active environment: according to production conditions, vapors are constantly or for a long time, or deposits are formed that act destructively on insulation and live parts of electrical equipment (premises for livestock and poultry, etc.).

8. Explosive rooms and outdoor installations: explosive mixtures of flammable gases or vapors with air or other oxidizing gases, as well as flammable dusts and fibers with air (garages, gas and oil storage facilities, etc.) may form.

9. Fire-hazardous premises and outdoor installations: combustible substances are stored or used here (barns, barns, etc.).

According to the degree of danger of electric shock to a person, the premises are divided into three categories:

Premises with increased danger: damp, hot, with conductive dust and conductive floors (metal, earth, reinforced concrete, etc.), as well as those in which a person can simultaneously touch metal structures that have a connection to the ground and metal designs of electric motors and other electrical apparatus;

Especially dangerous premises: especially damp or with a chemically active environment, as well as those in which two or more conditions of increased danger are combined;

Premises without increased danger: they do not have conditions that create an increased and special danger.

V tab. 2 an approximate characteristic of the premises of country houses, cottages and residential buildings is given from the point of view of installation and maintenance of electric lighting wiring, the use of household electrical appliances and mechanisms with an electric drive.

Attention!

Electrical wiring used in residential and country houses must be safe, reliable and economical. Incorrectly designed and carelessly executed electrical wiring can lead to overheating and ignition of building structures and finishing coatings.

The reason for this may also be the wrong choice of conductor cross-section.

Table 2. Characteristics of premises and outbuildings

Wires and cables

In order to save scarce wires with copper conductors, wires and cables mainly with aluminum conductors are currently used for electrical wiring.

Copper wires and cables are laid only in cases stipulated by the "Rules for the Construction and Operation of Electrical Installations", for example, in fire and explosion hazard rooms, in buildings with combustible ceilings.

The laying of wires and cables with aluminum conductors, in principle, does not differ from the laying of wires and cables with copper conductors, but it is carried out with greater care, in order to avoid damage to the conductors due to their lower mechanical strength compared to copper ones. When working with aluminum wires, you should not allow multiple bends in the same place, cuts of the cores when stripping the insulation.

A wire is one uninsulated or one or more insulated metal conductive core, over which, depending on the laying and operating conditions, there may be a non-metallic sheath, winding or braiding with fibrous materials. The wires can be bare and insulated.

Bare wires are those that do not have protective or insulating coatings on top of the conductive cores. Bare wires of the brands PSO, PS, A, AS, etc. are used, as a rule, for overhead power lines.

Insulated wires are those in which the conductive cores are covered with insulation, and on top of the insulation there is a braid of cotton yarn or a sheath of rubber, plastic or metal tape. Insulated wires are classified as protected and unprotected.

Protected are insulated wires that have a sheath on top of electrical insulation, designed to seal and protect against external climatic influences. These include wires of the APRN, PRVD, APRF brands, etc.

Insulated wires are called unprotected if they do not have a protective sheath on top of the electrical insulation (wires of the APRTO, PRD, APPR, APPV, PPV brands, etc.)

A cord is a wire consisting of two or more insulated flexible or highly flexible cores with a cross section of up to 1.5 mm 2, twisted or laid in parallel, covered with a protective insulating sheath.

A cable is one or more insulated conductors twisted together, enclosed in a common rubber, plastic, metal sheath (NVG, KG, AVVG, etc.).

For electrical wiring of power and lighting networks, carried out inside garden houses and summer cottages, as well as on the territory of garden plots, insulated installation wires and unarmored power cables with rubber or plastic insulation in a metal, rubber or plastic sheath with a cross-section of phase conductors up to 16 mm 2 are used.

The conductive cores of the installation wires have standard cross-sections in mm 2: 0.35; 0.5; 0.75; 1.0; 1.5; 2.5; 4.0; 6.0; 10.0; 16.0, etc.

The wire cross-section is calculated using the following formula:

S =? D 2/4,

where S is the cross-section of the wire, mm 2;

? - a number equal to 3.14;

D - wire diameter, mm.

The diameter of the current-carrying conductor (without insulation) is measured with a caliper or micrometer. The cross-section of the cores of stranded wires is determined by the sum of the cross-sections of all wires entering the core.

The insulation of the installation wires is designed for a specific operating voltage. Therefore, when choosing a brand of wire, it should be borne in mind that the operating voltage for which the wire insulation is designed should be greater than the voltage of the supply electrical network. The mains voltage is standardized: - line voltage 380 V, phase voltage - 220 V, and the installation wires are produced for a rated voltage of 380 V and above, therefore, as a rule, they are suitable for wiring.

The installation wires must be suitable for the connected load. For the same brand and the same wire cross-section, loads of different magnitudes are allowed, which depend on the laying conditions. For example, wires or cables laid openly cool better than those laid in pipes or hidden under plaster. Rubber-insulated wires allow a continuous heating temperature of their cores not exceeding 65 ° C, and plastic-insulated wires - 70 ° C.

The cross-section of the conductive conductors is selected based on the maximum permissible heating of the conductors, at which the insulation of the wires is not damaged. Permissible continuous loads on wires, cords and cables are given in tab. 3-7.

Brands of wires and cords with rubber and PVC insulation, their areas of application and methods of laying are given in tab. eight.

Table 3. Long-term permissible current loads (currents) on wires and cords with rubber and PVC insulation, as well as on bare wires of overhead lines

Table 4. Permissible loads on aluminum wires with rubber and PVC insulation

Table 5. Permissible loads on rubber-insulated copper wires in metal protective sheaths and cables with copper conductors, rubber-insulated in lead, polyvinyl chloride, nairite or rubber sheaths, armored and unarmoured

(*) Current loads refer to wires and cables with or without a grounding conductor.

Table 6. Permissible loads on copper wires and cords with rubber or PVC insulation
Table 7. Permissible loads on cables with aluminum conductors, with rubber or plastic insulation in aluminum, lead, PVC and rubber sheaths, armored and non-armored

Table 8. Fields of application and methods of laying insulated wires and cords with rubber and PVC insulation

Technical requirements for electrical wiring

Protected wires and cables such as APRN, APRV, AVRG, APRG, AVVG, etc. are allowed to be laid directly on the surface of walls and ceilings. The height of their laying in insulating pipes with a metal sheath or in flexible metal sleeves from the floor level is not standardized.

Open wiring with unprotected insulated wires in rooms without increased danger should be laid at a height of at least 2 m from the floor, and in rooms with increased danger and especially dangerous rooms - at a height of at least 2.5 m from the floor. If this condition cannot be met in a real situation, then such wiring must be protected from mechanical damage or protected wires and cables must be used.

Protection of electrical wiring in places of possible mechanical damage is carried out with steel boxes, corners, thin-walled pipes, metal hoses, fences or laid hidden.

With open laying of protected wires and cables with a sheath of combustible materials and unprotected wires, the clear distance from the wires (cable) to the surface of combustible bases must be at least 10 mm. To ensure this condition, rollers, insulators, clamps, etc. are used. If it is impossible to provide the specified distance, the wire or cable is separated from the surface with a layer of non-combustible material, for example, asbestos protruding from each side of the wire or cable by at least 10 mm.

With hidden wiring of wires and cables with sheaths of combustible materials and unprotected wires in the voids of building structures, in furrows, etc. with the presence of combustible structures, the wires and cables are protected with a continuous layer of non-combustible material from all sides where there is combustible material of the building structure.

When laying wires and cables openly along walls, partitions and ceilings, you must adhere to the architectural line of the room. Slopes to switches and sockets are laid vertically (along a plumb line); horizontal sections of the wiring - parallel to the cornices; branches to lamps - perpendicular to the lines of intersection of walls and ceiling. In rooms covered with wallpaper, it is recommended to carry the upper horizontal wiring above the upper edge of the wallpaper.

Apartment shields with an electric meter are installed at a height of 0.8–1.7 m from the floor in a place that excludes mechanical damage to the shield and has free access to maintenance (in case of emergency switching on and off of circuit breakers).

If the apartment panel has two or more circuit breakers, then the sockets and the network general lighting it is advisable to connect to different machines.

Connections and branches of wires and cables laid hidden or open in pipes and metal sleeves are performed in junction and branch boxes. Junction and branch boxes must be designed in accordance with the installation method and environmental conditions.

Making connections. Connections and branches of wires and cables are mainly performed on screw terminals or crimped. Single-core and twisted wires, laid openly on rollers and insulators, are connected by twisting, followed by soldering or welding.

The joints and branches of the conductors of wires and cables, connecting and branch clamps must have insulation equivalent to that of the wires, and also must not experience mechanical tensile forces. At the junctions of the conductors of wires and cables, their supply is provided, which ensures the possibility of re-connection. It is also necessary to be able to access for inspection and repair of joints and branches of wires and cables.

Junction boxes, boxes for switches and sockets for hidden wiring are embedded in a wall or partition so that their edges coincide with the surface of the plaster.

With hidden laying of wires before their final sealing with wet or dry gypsum plaster, check the wiring for breakage of current-carrying conductors of wires and short circuit in the network.

For the installation of electrical wiring in wet, damp rooms and outdoor wiring, lamps, wiring devices of a protected design with sealing caps and gland seals are used.

The height of the reinforcement suspension in rooms without increased danger must be at least 2 m from the floor to the cartridge. If the ceilings are low and these requirements cannot be met, then lamps are used in which access to the lamps is impossible without a tool. In rooms with increased danger and especially dangerous with a height of installation of lamps above the floor of less than 2.5 m, lamps are used, the design of which excludes the possibility of access to the lamp without a special tool, or lamps designed for a voltage not higher than 42 V.

The length of the wires in damp, damp and especially damp rooms should be kept to a minimum. It is recommended to place the wiring outside of these rooms, and the luminaires on the wall closest to the wiring.

Connection of copper and aluminum wires. The wires of the electrical wiring with the wires of the lamps are connected in the ceiling sockets. To connect the aluminum wires of the line with the copper reinforcing wires of the luminaires, clamping blocks are used.

When laying two or more flat wires in parallel with open and hidden wiring, the wires should be laid flat on the wall or ceiling, in rows with a gap of 3-5 mm. Laying flat wires in packages or bundles is not allowed.

In open electrical wiring, fastening of unprotected wires with metal brackets should be performed with an insulating pad installed between the wires and brackets.

Laying in pipes. When laying wires and cables in pipes, flexible metal sleeves, they provide the ability to replace wires and cables.

Hidden and open laying of wires and cables on heated surfaces (stoves, fireplaces, chimneys, etc.) is prohibited, since due to drying out of the insulation, wires and cables become unusable and, as a result, to a fire.

The bending radius of unprotected insulated wires must be at least three times the outer diameter of the wire; protected and flat wires - at least six times the outer diameter or width of a flat wire.

Cables with plastic insulation in a PVC sheath are laid with a bending radius of at least six times, and with rubber insulation - at least ten times the outer diameter of the cable.

Installation of all types of wiring is allowed at temperatures not lower than minus 15 C. At low temperatures, some insulating materials become brittle; when they are bent, cracks are formed in the insulation, which during operation can cause damage to wires and cables.

The types of electrical wiring and the methods of laying wires and cables are selected depending on the characteristics of the environment in accordance with the PUE, SNiP and in relation to the conditions of garden houses and cottages are given in tab. nine. For each type of wiring, method of its execution and environment, several brands of wires are indicated in the table. The first of the brands is preferable, and only if necessary, it can be replaced by the next one. Wires should be used for their main purpose, for example, wires APPV, PPV - for open laying directly on fireproof bases, APRTO - for laying in pipes, APRI - for open laying on rollers or insulators.

The selected type of wiring and the method of laying wires and cables must also comply with fire safety requirements ( tab. nine).

Table 9. Types of electrical wiring and methods of wiring, used depending on the environment

Notes:

1) Except especially damp rooms.

2) On casters for damp places.

3) It is prohibited to use steel pipes with a wall thickness of 2 mm or less in damp and especially damp rooms and outdoor installations.

4) With a lining of sheet asbestos with a thickness of at least 3 mm, protruding on both sides of the wire or pipe by 10 mm.

5) In a continuous layer of plaster, alabaster, cement mortar or concrete at least 10 mm thick.

6) In the plastering furrow, in a continuous layer of alabaster trail with a thickness of at least 5 mm or under a layer of sheet asbestos with a layer thickness of at least 3 mm.

7) Under a layer of wet plaster with a thickness of at least 5 mm.

8) Under a layer of cement or alabaster basting at least 10 mm thick.

9) Plastering of the pipe is carried out with a continuous layer of plaster, alabaster with a thickness of at least 10 mm.

10) In a continuous layer of alabaster (cement) basting with a thickness of at least 10 mm or between two layers of sheet asbestos with a thickness of at least 3 mm, protruding from each side of the wire by at least 10 mm.

11) Under a layer of wet plaster with a lining for the wire, a layer of sheet asbestos with a thickness of at least 3 mm or according to the outline of a plaster with a thickness of at least 10 mm, protruding from each side of the wire by at least 10 mm.

Table 10. Selection of the type of electrical wiring and methods of laying wires and cables according to fire safety conditions

Electrical work on wiring

Before purchasing electrical materials and devices and starting electrical work, the owner of a garden house or cottage needs to solve a number of preparatory issues:

Draw up a schematic diagram of the electrical wiring, tying it to the planning drawing of a garden house or cottage;

Determine the type of wiring (open, hidden) and the method of laying wires and cables, depending on the environmental conditions and premises by the degree of relative humidity. In areas with high humidity, the requirements for both materials and the quality of electrical work are significantly increased;

Determine the degree of flammability of building materials;

Think over the type of lighting, depending on the purpose of the room, lighting standards, choose the type and design of lamps: ceiling or wall, with incandescent or fluorescent lamps;

Determine the number and location of sockets, switches, junction boxes, routing of wires and cables;

Determine the power consumption of electrical consumers, accordingly select the type of meter and the type of protection;

Determine the cross-section of wires and cables.

Internal wiring

Internal wiring consists of the following operations:

Layout work;

Making passes and intersections;

Installation of electrical wiring;

Installation of switches, plug sockets, lamps;

Installation of apartment panels;

Checking the wiring.

The markup is carried out before the start of finishing work in the premises of the garden house or cottage. When marking, take into account the ease of use and maintenance of wiring in operation, as well as compliance with the rules of electrical and fire safety.

Wire routes for hidden laying should be easily determined during the operation of the wiring.

To eliminate the likelihood of accidental damage to the wiring during the subsequent installation of wall paintings, clocks, carpets, etc., the hidden wiring route is selected based on the following:

Horizontal laying along the walls is carried out parallel to the lines of intersection of the walls with the ceiling at a distance of 10–20 cm from the ceiling. The mains of the socket-outlets are laid along the horizontal line connecting the socket-outlets;

Descents and ascents to switches, sockets and lamps are performed vertically at a distance of 10 cm parallel to the lines of door and window openings or corners of the room;

Concealed wiring on ceilings (in plaster, in cracks and voids of reinforced concrete slabs) is performed along the shortest distance between the most convenient place to go to the ceiling from the branch box to the luminaire;

The marking of hidden wiring routes, deepened into the furrows of walls and ceilings, can be carried out in the shortest direction from the inputs to the power consumers;

Wires and cables are laid in places where the possibility of their mechanical damage is excluded, in other cases they must be protected.

Lighting switches or lanyard with pre-ceiling switches set:

In accessible places on the wall by the door, from the side doorknob so that they are not closed by the door when it is opened;

For toilets, baths and other rooms with damp and especially damp conditions - in adjacent rooms with better environmental conditions;

In the pantries, basements, in the attic and in other locked rooms - in front of the entrance to these rooms;

At a height of 1.5–1.8 m from the floor of the room.

Plug sockets are planned to be installed in places convenient for use, depending on the purpose of the room and interior design. They must be located at a distance of at least 0.5 m from grounded metal structures (heating pipelines, water pipelines, gas pipelines, etc.); for kitchens this distance is not standardized.

Installation requirements for wall outlets:

The installation height of sockets in rooms and kitchens from the floor is not standardized;

Above-plinth type sockets are installed at a height of 0.3 m from the floor;

Plug sockets are set for a current of 6 A from the calculation: in living rooms - one socket for 10 m 2 of the room area, in kitchens - two sockets, regardless of the area;

In damp, damp and especially damp rooms (kitchens, bathrooms, toilets, etc.), you should:

Reduce the length of laying wires and cables with the greatest distance from water supply and sewerage pipes;

Switches are placed outside these premises, and lamps are placed on the wall adjacent to the corridor;

Installation of plug sockets in bathrooms, showers and toilets is not allowed;

In these rooms, as a rule, hidden electrical wiring is used; wires are laid in PVC or other insulating pipes;

Open wiring with protected wires and cables is allowed;

Wiring in steel pipes is prohibited.

Electrical work begins with marking the installation locations of junction and branch boxes, apartment panel, plug sockets, switches, lamps, since their location determines the beginning, direction and ends of the routes.

Layout of lines for laying wires. After the marking of the installation sites is completed apartment meter, switches, sockets, fixing points for fixtures, mark lines for laying wires. Lines are beaten off, as a rule, with the help of a cord. The cord is rubbed with a coloring material (chalk, coal, etc.). When marking, the cord is pulled in the desired direction, pulled and then released sharply, thus beating off a clear visible line on the wall or ceiling, showing the direction of the wiring route.

The places of installation of fasteners (rollers, insulators, staples, fasteners, etc.) are marked with short lines drawn across the line broken off by a cord.

The installation locations of the supporting structures and fasteners are determined in the following sequence:

First, at junction and branch boxes, at turns, at transitions through walls and ceilings, and then mark the points of intermediate fasteners;

Places of installation of fasteners are located along the route symmetrically at the same distance from each other, not exceeding the maximum allowable SNiP;

The attachment points of the wires when they are inserted into the box or when passing through the wall are located at a distance of 5–7 cm, and at bends and turns at a distance of 1.0–1.5 cm from the beginning of the bend;

On straight sections, the dimensions between the supporting supports are selected in accordance with the recommendations tab. eleven.

Table 11. Standard dimensions when laying wires on insulating supports

In fig. 2 shows an example of the marking distances of the electric wiring on rollers.

Rice. 2. Marking distances of electric wiring on rollers: a - for laying routes; b - for installing switches; c - to avoid obstacles: 1 - funnel; 2 - rubber semi-solid tube; 3 - heating pipe

When marking, they use measuring rulers, plumb lines, folding rules and tape measures, a marking pole, marking compasses, levels and other special tools and devices. In addition, when marking, it is necessary to have a stepladder and marking templates for marking the holes for fastening the socket outlets, sockets and switches.

Open wiring with rollers and insulators

Open wiring using rollers and insulators is still widely used in suburban construction. V tab. 12 recommendations are given on the choice of installation materials when installing open wiring using insulated wires.

When installing the rollers on wooden walls, they are fixed with screws with a semicircular head. If the rollers are placed in a row on plastered walls and ceilings, then a steel strip is placed under them - a bar that protects the plaster from destruction.

On brick and concrete walls, the rollers are fixed on fasteners or brackets (Fig. 3 a, b) with screws or bolts. Staples and fasteners are smeared into the holes knocked out in the wall with alabaster or cement mortar. The rollers can also be installed using a wire spiral. The spiral is made of galvanized knitting wire with a diameter of 0.5–0.8 mm.

Rice. 3. Fastening of rollers: a - by fastening; b - a bracket; in - a wire spiral; d - on dry plaster; d - using a dowel or PVC tube on a brick wall: 1 - spiral; 2 - alabaster solution; 3 - fastener made of steel with a thickness of 0.5 mm; 4 - dry plaster; 5 - dowel or PVC tube; 6 - brick wall

Table 12. Installation materials for insulated wires of brands PR, PV, APR, APN, APV

(*) The length of the screws corresponds to the length at which the rollers are attached to unplastered wood. For attachment to the plastered wood, the length of the screws is increased by the thickness of the plaster layer - 20–30 mm.

A hole for a spiral, punched in the wall with a bolt or bored with a winder drill, is filled with alabaster mortar and a screw with a spiral is inserted into it. As the mortar sets, the screw is turned out, and then a roller is installed in this place. This method is recommended for wires with a cross-sectional area of ​​up to 2.5 mm 2.

There are a number of other ways to attach rollers to brick and concrete substrates. Currently, the most convenient and reliable method of fixing the rollers using self-locking spacer metal, nylon and polyethylene dowels (Fig. 3 e). Nylon, polyethylene dowels are available for screws with a diameter of 3.5 and 5 mm. The dowels are cylindrical with outer annular ribs and longitudinal cuts. The ribs ensure reliable fixing of the dowel into the hole when the screw is screwed into it. The hole diameter should not exceed the dowel diameter by more than 1.0–1.5 mm. The depth of the hole must be such that the dowel is in brick or concrete, not just in plaster.

For fastening the rollers to dry plaster, special fasteners are used (Fig. 3d). When mounting, a hole is made in the surface into which the fastener is inserted. The fastener is wound behind the surface of the plaster opposite to the roller, after which a screw with a roller is screwed into it.

Insulators are installed on hooks, anchors, semi-anchors, pins, and with a large number of them, on brackets, which are reinforced in nests, in walls or on the ceiling with alabaster mortar (in brickwork) or cement mortar (in concrete walls). To seal the insulator on a hook or anchor, tow tow is wound onto the bar with burrs, and then the insulator is screwed on. In fig. 4. the fasteners for the insulators are shown. Hooks and brackets with insulators are fixed only in the main material of the walls, and frames for wires with a cross-section of up to 4 mm 2 inclusive are fixed on plaster or cladding of wooden buildings.

Rice. 4. Fasteners for insulators: a - a hook with a shank for screwing into a tree (above) and for embedding in concrete and brick walls; b - anchor; c - half anchor

Open wiring with twisted single-core wires PRD, PRVD

The laying and fastening of the wire is carried out after installing the rollers. The wire is delivered to the place of installation in bays. It is carefully unwound, measured according to the markings. The wire is straightened by passing it through a rag soaked in paraffin. Two measured pieces of wire are tied on the extreme roller and twisted together with a twist step of 5–7 cm. Having reached the first intermediate roller, the wires are passed along the roller neck and fixed in accordance with the recommendations in fig. 5. The wires are fixed in the same way on the remaining intermediate and outer rollers. A branch on twisted wiring to the switch and the luminaire is made in accordance with Fig. 6. The device of passages and bypasses is shown in fig. 7.

Rice. 5. Methods of binding wires to rollers: a - with a cross with a clamp; b - with a cross; c - PVC rings; g - viscous: 1 - wire APR1? 6; 2 - RP-6 roller; 3 - knitting wire; 4 - insulating tape; 5 - PVC ring; 6 - wire PRVD

Rice. 6. Branching of wires when laying wires of APR and PRVD on rollers: 1 - screw; 2 - knitting wire; 3 - RP-6 roller; 4 - wire APR1? 6; 5 - insulating tube; 6 - wire APR1? 4; 7 - to the switch; 8 - to the switch and lamp

Rice. 7. Passage of wires through the wall: a - from a damp to a dry room; b - from a dry room to a dry one: 1 - sleeve; 2 - insulating tube; 3 - funnel; 4 - wire

Passages through walls and interfloor ceilings are made in insulating tubes. At the outlet, porcelain funnels (in damp rooms) or bushings (in dry rooms) are put on the tubes. They are embedded in the wall with alabaster mortar. In this case, each wire is enclosed in a separate insulating tube. A double wire in a wall passage is allowed to be laid in one pipe (in dry rooms). In the furrows, wires are laid when avoiding obstacles. When passing through a wall, the hole of the funnel is turned down. If the wires pass into a damp room with a different temperature, humidity, etc., the funnels are poured on both sides with a sealing mass (bitumen mass). Open passages through the internal walls of normal non-explosive and non-fire-hazardous premises need not be sealed.

Open wiring with single-core wires APV, PV, APRI, PRI

Single-core insulated wires are allowed to be laid on rollers in dry and damp, heated and unheated rooms, as well as under sheds and in outdoor electrical wiring. An independent row of rollers should be installed for each core. The distance between the rows of rollers is 35 mm, and between the rollers along the track in accordance with Table 11.

The prepared wire is tied to the extreme roller, stretched along the route, the branch points are marked on it. After that, the wire is removed, branches are attached to it, pulled again and finally tied to the extreme roller on the other side. After that, the wire is tied up on intermediate rollers. The wire tie technology is shown in Fig. 5.

The wires are tied with soft annealed wire with a corrosion-resistant coating. The diameter of the wire for tying wires with a cross section of 2.5 mm 2 is not less than 0.6 mm. In the places of knitting, two or three layers of insulating tape are applied under the wire.

The wires to the rollers can be secured with copper strands of the remaining wire cuttings. For fastening to intermediate rollers, you can use rings cut from a polyvinyl chloride tube with a diameter of 40 mm and a wall thickness of 1.5–2 mm.

The branches of the wires are performed only on rollers. The intersection of the branch wire with the main line is protected by an insulating tube that is put on the branch wire (Fig. 6).

Passages through walls with single-core wires are performed in the same way as with PRD, PRVD wires. In this case, each core is laid in a separate pipe.

The installation locations of lamps, switches, and sockets are marked in the same way as when laying with twisted wires.

Open wiring with flat wires APPV, PPV on rollers

Wiring with flat wires is allowed for existing buildings, as well as for newly constructed small residential, summer cottages, garden and cottage buildings on unplastered wooden walls, ceilings and partitions on rollers and clamps.

The rollers and clamps are fixed on the surface with screws according to the previously described markings.

Flat wires are attached to rollers in two ways:

1st method of securing. After fixing all the rollers, the wire is unwound from the coil, straightened and measured to the desired length. Then a longitudinal cut is made along the line of contact of the veins so that the roller head can pass through the resulting hole. The wire is put on the head of the extreme roller and fixed with a knitting wire or braid in the same way as when installing electrical wiring with PRD, PRVD wires. Next, the wire is pulled to the next intermediate roller; on the wire opposite the roller, the following longitudinal cut is made along the line of contact of the cores. The roller head is passed through the resulting hole, then the wire is fixed in the same way on the remaining rollers.

2- The th method of fixing a flat wire on rollers (similar to fixing a wire on the clamps) is as follows:

When installing the roller under the head of the screw, place strips of sheet metal 15 mm wide and 50–80 mm long. The most commonly used white sheet metal;

After fixing the entire row of rollers, the flat wire is placed on the head of the screw with a gasket of insulating material 17 mm wide;

After laying the wire, the ends of the metal and insulating plate are bent with a lock (or fastened with a buckle). The wire is pulled to the next roller and fixed the same way(Fig. 8 a).

Rice. 8. Laying of wires on rollers, examples of bending of wires: a - APPV wire on rollers; b - wires APPV, APN, APR, APRV on wooden bases on the clamps; c - an example of bending of wires of the APPV and APPR brands; d - an example of bending of wires of brands APV, APN and APRV to the edge: 1 - wire APPV 2x6; 2 - strip; 3 - buckle; 4 - a gasket made of electrical cardboard; 5, 9 - screws; 6 - RP-2.5 roller; 7 - APR wire; 8 - clitoris; 10 - wire ALP 3x4

Laying of flat wires of APN, APR, APV, APRV brands on clamps. In this case, the flat wire is attached to the wall through the claw with a screw through the hole in the separating film between the cores. In this case, it is necessary to put an insulating washer under the screw head and, when screwing in the screw, be careful not to damage the wire insulation (Fig. 8 b).

When bending flat two- and three-core wires by 90 °, a separating film between the cores at the bend is cut out, one or two cores are taken inside the corner in the form of a half-loop (Fig. 8 c). When the track is turned by 90 °, a two-core and three-core wire of the APN type is bent on the edge, having previously cut the separating film, while the inner core at the turning point is partially superimposed on the outer one (Fig. 8 d). Single-core wires of the APN, APV and APRV brands are bent with a radius of 20 mm when the cross-sectional area is up to 10 mm 2, and with a radius of 35 mm if the cross-sectional area is from 16 to 35 mm 2.

Fastening flat wires to concrete and brick foundations. Flat wires have light-resistant insulation, so they can be used in open electrical wiring directly along walls, partitions and ceilings made of non-combustible materials, while flat wires are attached to concrete and brick bases using a steel strip (tape) 20-40 mm wide and 3– 4 mm, which is nailed to the wall with dowel-nails along the entire wiring route (Fig. 9). The distance between adjacent dowel-nails is no more than 1 m.

Rice. 9. Fastening of wires of brands АПВ, АППВ, АПН, АПРВ to concrete bases on the target steel strip: a - fastening the strip with a dowel-nail; b - wire fastening: 1 - strip; 2 - dowel-nail; 3 - electrical cardboard gasket; 4 - wire APN 3? 4; 5 - mounting tape; 6 - mounting button

The wires are fixed to the tape every 30–40 cm with strips 10 mm wide made of tinplate, galvanized or painted steel sheet, or with the help of normalized mounting perforated strips and buckles. The wires under the strips must be protected with insulating cardboard spacers protruding 1.5–2 mm on both sides of the metal strip.

Figure 10a shows the fastening of wires of the APV, APPV, APN, APRV brands to concrete and brick foundations along a targeting wire, and figure 10b - using targeting fasteners with strips.

Rice. 10. Fastening of wires of brands АПВ, АЛПВ, АЛН, АПРВ to concrete and brick foundations: a - along the wire to be targeted; b - on the fastened fasteners with strips: 1 - plate; 2 - dowel-nail; 3 - wire; 4 - APN 3x4; 5 - gasket made of electrical cardboard; 6 - steel strip; 7 - buckle

Laying wires on glued fasteners. Plastic or steel fastening parts for flat wires and cables of the AVRG and ANRG brands can be glued to concrete, reinforced concrete, expanded clay concrete, asbestos-cement, brick and ceramic bases, the surface of which is dry, durable, free from dust, dirt and soot, using special adhesives, for example, glue KNE-2/60 (electrotechnical coumaron sodium) or BMK-5K based on acrylic resin with kaolin filler.

Do not glue wires directly to the building base.

Plastic and metal parts are degreased with acetone or gasoline before gluing. The quality and strength of adhesion depends on adherence to technology. First, you need to clean the base with a metal brush and apply the glue with a spatula to the building base on an area slightly larger than the size of the part to be glued. Then apply glue to the part to be glued and press it against the building base for 3-5 seconds.

You can start electrical work after the glue has completely dried (20-25 hours). The glue can only be used at room temperature over 5 C and relative humidity no more than 70%.

When performing installation work using glue, it is necessary to observe the fire safety rules adopted for flammable liquids, to avoid getting glue on the skin of the hands, face and eyes. In fig. 11 shows some other methods of attaching wires and cables to concrete, brick and the like.

Rice. 11. Fastening wires of brands APV, APPV, APN, APRV and cables AVRG and ANRG to concrete and brick foundations: a - using a strip nailed with a dowel-nail (manual driving); b - with plastic brackets; c and d - using staples with one and two legs; d - using a strip embedded in the base: 1 - dowel-nail; 2 - APN wire 3? 4; 3, 10 - strip; 4 - a gasket made of electrical cardboard; 5 - plastic bracket; 6 - bracket; 7 - screw; 8 - nylon dowel; 9 - cable AVRG (ANRG) 3 × 10 + 1 × 6; 11 - buckle; 12 - alabaster

Laying on wooden structures. Flat protected wires АППР and cables in a sheath made of non-combustible and non-combustible materials are allowed to be laid along wooden walls, partitions, ceilings and other combustible structures with fastening with staples.

It is also allowed to lay on combustible structures of unprotected wires with PVC insulation with a mandatory lining for the wires of insulating non-combustible materials, for example, sheet asbestos with a thickness of at least 3 mm, protruding from each side of the wire by at least 10 mm.

Concealed wiring with flat stranded wires

Hidden wiring inside premises is carried out in steel water and gas pipes (only in explosive areas), thin-walled and electrically welded pipes (in fire-hazardous premises), in flexible metal hoses, boxes, in plastic (polyethylene, polypropylene and vinyl plastic), as well as in rubber-bitumen pipes.

Laying on non-combustible substrates. In residential buildings, permanent hidden laying of wires APPV, APN, APPVS is allowed directly on panels of fireproof structures - under plaster, in grooves of walls, in the seams between floor panels, etc., as well as directly under a layer of wet plaster in the thickness of the base or in continuous a layer of alabaster trail (Fig. 12 a).

Rice. 12. Concealed laying of wires: a - wires of the APPVS, APN, APV brands on fireproof bases under wet and dry plaster; b - the same wires on wooden bases under dry plaster; c - on wooden bases under wet plaster: 1 - wire APPVS; 2 - alabaster; 3, 13 - wet plaster; 4 - plaster basting; 5 - a nail; 6 - alabaster gasket; 7 - strip; 8 - dry plaster; 9 - APN or APV wire; 10 - rail; 11 - plaster shit; 12 - contour of wet plaster

On wooden bases covered with dry plaster, the wires are sealed with a continuous layer of alabaster tarmac or between two layers of sheet alabaster (Fig. 12 b).

On wooden walls and partitions covered with wet plaster - under a layer of plaster with a lining for asbestos sheet wires with a thickness of at least 3 mm or according to a plaster outline with a thickness of at least 5 mm. Asbestos or plaster basting is laid on top of the shingles, or shingles are cut to the width of the asbestos gasket. The width of the asbestos spacer must be such that the asbestos protrudes at least 10 mm on each side of the wire.

On wooden walls and partitions covered with a layer of dry gypsum plaster - in the gap between the wall and the plaster in a continuous layer of alabaster tarmac or between two layers of sheet asbestos 3 mm thick. In this case, the layer of alabaster tarmac or asbestos on each side of the wire must be at least 10 mm.

Concealed flat wire laying technology

When installing wiring with flat wires with hidden wiring, a number of operations are performed:

Wire straightening from the coil;

Route marking;

Wire laying;

Fastening the wire;

Bending and crossing the wire;

Passages through walls and ceilings.

To straighten flat wires, one end of the wire is fixed in a vise, after which the wire is pulled through a cloth or mitten. When melting single-wire wires with PVC insulation (PV, APV, etc.), it is not recommended to pull the wires with great effort, since the insulation can move.

Wiring is carried out in sections: apartment panel - branch box - plug socket; branch box - switch; junction box - luminaire, etc.

The wires are connected to each other only in junction boxes. Connecting wires to each other outside the boxes is not allowed. The wire is cut into pieces equal to the length of the individual sections. The wire is laid with light pressure along the entire length straight section from the box to the turn of the track and fix it with alabaster mortar (Fig. 12 a).

When the wire is rotated, the separating base is cut out to enable the wire to rotate in a plane.

After laying the wire at the turn, it is fixed with alabaster mortar. Similarly, the installation of the wire is carried out on the entire remaining route to the next box.

Providing wire connectivity. When installing the wiring, it must be possible to freely make wire connections in junction boxes, boxes for switches and sockets. Such a need may arise during the period of operation for the repair or replacement of switches, sockets, lamps. Therefore, the ends of the wire with separate cores are inserted into the boxes with a margin of 5070 mm. After that, the wire at the box is fixed.

For connection to luminaires, plug sockets, switches of open installation, hidden wires are put on the places where they exit from walls, partitions and ceilings, insulating tubes, porcelain or plastic bushings or funnels are put on in order to prevent the wires from breaking due to their repeated bending.

Wall penetrations of flat wires with hidden wiring are also made in insulating pipes, while the installation of porcelain bushings and funnels is not required.

Electrical wiring in steel and plastic pipes

Wiring in pipes is carried out only in cases when the use of other methods of installation is not recommended. Pipe wiring is used to protect wires from mechanical damage, as well as to protect wire insulation from adverse environmental conditions. To protect against mechanical damage, the pipeline itself can be made leaky, and to protect it from the external environment, the pipeline is made hermetically sealed.

The tightness of the pipeline is ensured by sealing the joints between the pipes and their connection to branch boxes and various electrical consumers.

When crossing with heating pipes, the distance to the wiring pipes must be at least 50 mm in the light, and when laid in parallel with them - 100 mm.

Steel pipes must be laid so that moisture and condensation cannot accumulate in them. To drain water, pipes are laid on horizontal sections of the route with a slight slope towards the box.

In steel and plastic pipes, unprotected insulated wires of the APRTO, PRTO, APV, PV, etc. brands are laid.

The minimum cross-sections of conductive conductors of insulated wires laid in pipes are 1.0 mm 2 for copper and 2.0 mm 2 for aluminum wires.

Wiring is installed in pipes so that, if necessary, the wires can be removed from the pipe and replaced with others. Therefore, if there are two bending angles on the pipeline route, then the distance between the boxes should not exceed 5 m, and on straight sections - 10 m.

It is forbidden to make connections or branches of wires in pipes, they are performed only in boxes.

The execution of electrical wiring in steel pipes can be carried out with open, hidden and external laying. Steel pipes are used as an exception when laying wires without pipes is not allowed and non-metallic pipes cannot be used.

In garden houses and buildings, steel pipes are required for the installation of inputs and electrical wiring in attics, in basements and for outdoor electrical wiring.

Pipes are cleaned of rust, dirt, burrs before installation. To prevent the destructive effect of corrosion products on the sheath of wires and cables, pipes laid openly are painted. Pipes laid in concrete are not painted on the outside for better adhesion of their outer surface to concrete.

When bending pipes, crushing (corrugation) at the corners is not allowed. It is not recommended to bend the pipes to an angle of less than 90 °, since it is difficult to pull the wires through the pipes with a complex configuration of pipelines and its long length. Therefore, the bending radii of the pipes are limited. When laying pipes, the bending radius must be at least six outer diameters of the pipe, with one bend or open laying - at least four outer diameters. When laying a pipe in concrete, the bending radius must be at least ten outside pipe diameters.

The distance between the attachment points of openly laid steel pipes in horizontal and vertical sections depends on the diameter of the pipes to be laid. Pipes with a diameter of 15–32 mm are fixed every 2.5–3.0 m, and at bends - at a distance of 150–200 mm from the angle of rotation. When pipes are laid open, they are attached to the supporting structures with brackets, clamps, linings and clamps.

After cutting, the ends of the pipes are cleaned of burrs, countersunk and terminated with bushings that protect the insulation of the wires from damage at the point of entry and exit from the pipe.

Steel pipes are interconnected with threaded couplings, unthreaded couplings, cuffs, as well as using junction and branch boxes and boxes. Connect the pipes with threaded couplings so that the pipeline can be easily disassembled at any time. Branches and connections are carried out in boxes with lids. The boxes are connected to pipes with threads or with clamps.

For open and hidden installation in damp, especially damp, fire-hazardous rooms, attics and outdoor installations, the joints of steel pipes must be sealed. Sealing of the joints of pipes and places of entry into boxes is performed with standard threaded couplings with hemp on drying oil, red lead.

When laying steel pipes openly in dry, non-dusty rooms, the pipes themselves, as well as the pipes and boxes, are connected without seals: sockets, cuffs on screws and bolts, sleeves, etc.

Laying of plastic pipes. For open laying in dry, humid, especially damp and dusty rooms, in rooms with a chemically active environment and in external wiring, on non-combustible and hardly combustible bases, plastic pipes are used.

The connection of plastic pipes and assemblies is carried out by welding using special torches, tools and fixtures. The bending radius of plastic pipes is taken to be at least 6 times the outer diameter of the pipe. Plastic boxes must be used for electrical wiring.

Fasten plastic pipes with brackets that allow free movement of pipes with temperature deformations up to 5 mm per 1 m of pipe.

The choice of steel and plastic pipes for wiring is made in accordance with tab. 13.

Table 13. Selection of steel and plastic pipes for laying insulated wires APR, APV, APRV, APRTO

If the length of the continuous piping exceeds:

50 m - if there is no more than one bend;

40 m - in the presence of two bends;

20 m - in the presence of three bends (angles of 90 ° or more), then intermediate broaching boxes should be installed and only in extreme cases, pipes of a larger diameter should be used.

Connection and termination of wires

Installation of electrical wiring, connection of switches, sockets, sockets, etc. cannot be carried out without connecting and terminating wires. Correct and high-quality connections and connections to a greater extent determine the reliability of the power supply.

Requirements for wire connections. The connection of the conductors to each other and their connection to wiring devices must have the necessary mechanical strength, low electrical resistance and retain these properties for the entire period of operation. Contact connections are subject to load current, heat up and cool down cyclically. Changes in temperature and humidity, vibration, the presence of chemically active particles in the air also have an adverse effect on contact connections.

The physical and chemical properties of aluminum, from which the conductors are mainly made, make it difficult to make a reliable connection. Aluminum has (in comparison with copper) increased fluidity and high oxidizability, while a non-conductive oxide film is formed, which creates a large transition resistance on the contact surfaces. This film must be carefully removed from the contact surfaces before joining and measures must be taken to prevent its reoccurrence. All this creates some difficulties when connecting aluminum wires.

Copper conductors also form an oxide film, but unlike aluminum, it is easily removed and does not significantly affect the quality of the electrical connection.

A large difference in the coefficients of thermal linear expansion of aluminum in comparison with other metals also leads to contact failure. Given this property, aluminum wires cannot be crimped into copper lugs.

During long-term operation under pressure, aluminum acquires the property of fluidity, thereby breaking the electrical contact, therefore, mechanical contact connections of aluminum wires cannot be pinched, and during operation it is required to periodically tighten the threaded contact connection. Contacts of aluminum conductors with other metals in the open air are exposed to atmospheric influences.

Under the influence of moisture, a water film with the properties of an electrolyte forms on the contact surfaces; as a result of electrolysis, cavities are formed on the metal. The intensity of shell formation increases when an electric current passes through the place of contact.

Compounds of aluminum with copper and copper-based alloys are especially unfavorable in this respect. Therefore, such contacts must be protected from moisture or covered with a third metal - tin or solder.

Connection and termination copper wires

It is recommended to connect, branch off copper wires with a cross-section of up to 10 mm 2 by twisting followed by soldering, and copper single-wire wires with a cross-section of up to 6 mm 2, as well as stranded wires with small cross-section areas, are brazed along the twist (Fig. 13). The cores with a cross-sectional area of ​​6-10 mm 2 are connected by bandage soldering (Fig. 14 a), and the stranded wires are connected by twisting with preliminary unwinding of the wires (Fig. 14 b). The length of the joints by twisting or brazing must be at least 10-15 outer diameters of the wires to be connected. Soldered with lead-tin solder using a rosin-based flux. It is not allowed to use acid and ammonia when soldering copper wires, since these substances gradually destroy the soldering points.

Rice. 13. Connection by twisting followed by soldering: a - connection of wires PR and APR; b - branch of wires PR and APR; в - connection of wires of PRVD; PC - soldering point

Rice. 14. Connection and branching of wires: a - connection of single-wire bands by soldering; b - connection of stranded wires by twisting; in - a branch of stranded wires; d - connection of stranded wires by crimping

Crimp connection. The method of connecting copper wires by crimping is widely used (Fig. 14 d). The ends of the wires are stripped by 25–30 mm, then wrapped with copper foil and crimped with special pliers such as PK.

Connecting and terminating aluminum wires

Aluminum conductors of wires are connected by welding, soldering and mechanically (Fig. 15).

Rice. 15. Connection of wires by welding and soldering: a - connection of single-wire aluminum wires by welding in a sleeve; b - samples of welds; c - solder connection

Aluminum wires are welded in a special mold using carbon electrodes powered by a welding transformer.

For soldering, aluminum wires are twisted (Fig. 15 c), and then the place of twisting is heated in the flame of a blowtorch and soldered with solders, the compositions of which are given in tab. fourteen.

Table 14. Composition and melting point of solders

The technology for soldering aluminum wires is as follows:

Remove the insulation from the ends of the wires to be connected, then strip the bare cores to a metallic sheen and overlap with a double twist to form a groove at the point where the cores touch. The length of the groove for connecting and branching with different cross-sections of conductors is shown in Fig. 16;

Rice. 16. Soldering solid cores

The twisted wires are connected with a flame of a gas torch and a blowtorch to a temperature close to the melting point of the solder. After that, wipe the groove (with pressure) on one side of the connection with a solder stick previously introduced into the lamp flame. As a result of friction, the oxide film peels off, the groove begins to be tinned and filled with solder as the junction warms up. No flux is required. Then the groove is tinned and soldered on the other side of the joint. At the same time, wipe and irradiate the outer surfaces and twisting of the veins of the connected section with solder;

Clean the soldering points of the wires to be connected, wipe with a cloth soaked in gasoline, cover with a moisture-proof varnish and insulate with insulating tape.

The termination of the wires is performed after they have been laid. Single-wire wires with a cross-sectional area of ​​up to 10 mm 2 and stranded wires with a cross-sectional area of ​​up to 2.5 mm 2 are connected directly to the current collectors. In this case, the bare core is inserted under the clamping contact screw. The ends of the stranded wires are twisted and soldered. Depending on the type of contact, the end of the wire can be given the form of a pestle (Fig. 17 a) or a ringlet (Fig. 17 b).

Rice. 17. Termination of wires: a - with a pestle; b - a ring; c - tip soldering: 1 - tip; 2 and 3 - insulating tape or bandage thread

The ends of single-wire wires with a cross-section of more than 10 mm 2 or stranded wires with a cross-section of more than 2.5 mm 2 are equipped with lugs (Fig. 17 c), which are soldered or welded to the core, and in some cases are crimped.

In all cases of connection, branching and termination of wires, the places where they are connected to each other and the tip are wrapped with insulating tape in several layers. In accordance with the rules, the dielectric strength of the insulation at the point of connection or branch should not be lower than the strength of the insulation as a whole.

In suburban conditions, for connecting aluminum and copper wires to each other, the most acceptable method of connection is with screw clamps, since no special tools and devices are required. Contact design should provide constant pressure and limit wire squeezing out. It is necessary to assemble the clamp when connecting aluminum wires with all factory parts (screw, pressure washer, flat washer, contact plate), since the absence of any part will necessarily lead to deterioration of the contact.

To connect the wire to the clamp, the insulation is removed from the end of the wire. The knife is held at an angle of 10-15 ° to the surface of the core, this eliminates the cut of the aluminum core. The wire is stripped to a metallic shine and lubricated with quartz-vaseline paste, then the end of the core is bent in the form of a ring. Bend the wire clockwise, i.e. in the direction of rotation of the fastening screw.

The inner diameter of the ring should be slightly larger than the diameter of the contact screw (Table 15).

Table 15. Parameters of the ring on the terminated wire

The connection of wires by crimping is widely used in the installation of internal and external electrical wiring and overhead power lines.

This method provides reliable contact, the required mechanical strength, and is easy to implement. Crimping is performed with manual pliers, mechanical and hydraulic presses using replaceable dies and punches.

To connect the cores, sleeves GAO, GA are used, for termination - tips TA, TAM, etc.

Aluminum conductors in connecting sleeves are crimped according to the following technology:

The type and size of sleeves, as well as dies and punches, are selected in accordance with the dimensions of the sleeves;

Check for the presence of factory grease in the sleeves and tips, in the absence of lubrication, the sleeves and tips are cleaned with a metal brush and lubricated with a protective quartz-vaseline or zinc-vaseline paste;

The insulation is removed from the ends of the cores: when terminating - at a length equal to the length of the tubular part of the tip, and when connecting - at a length equal to half the length of the sleeve;

They clean the ends of the current-carrying veins sandpaper to a metallic shine, wipe with a cloth soaked in gasoline, and cover with quartz-vaseline paste;

A tip or a sleeve is put on the prepared cores;

When terminating, the core is inserted into the tip until it stops, and during connection - so that the ends of the cores to be connected are in contact with each other in the middle of the sleeve;

Install the tubular part of the tip or sleeve into the matrix and carry out pressure testing;

Insulate the connection with several layers of insulating tape.

It is not allowed to pressurize a copper tip on an aluminum conductor, since the connection will be fragile due to the large difference in the coefficient of linear thermal expansion between copper and aluminum.

Crimping of single and stranded copper conductors with a cross section of 4 mm 2 or more is performed in copper tubular lugs of the T type or connecting copper sleeves of the GM type. The technology for crimping copper wires is similar to the technology for crimping aluminum wires, with the exception of the imposition of quartz-vaseline or zinc-vaseline paste. Do not press with a hammer and chisel.

Installation of switches, plug sockets

Wiring accessories include: switches and switches; plug connections - plugs and socket; sockets for electric lamps; circuit breakers.

The wiring product must not be overloaded by current. Loading in excess of the rated current leads to burning of the contacts, impermissible overheating and can cause a fire.

Switches and sockets are available in two versions: for exposed wiring and for hidden wiring.

Sockets with open wiring are installed on socket outlets. Socket boxes are discs with a diameter of 60–70 mm, a thickness of at least 10 mm, made of non-conductive material (wood, textolite, hetikans, plexiglass, etc.). The socket boxes are fixed on the wall with countersunk screws or glued with BMK-5 or KNE-2/60 glue. On brick or benton walls, the socket boxes are also fixed with screws, having previously drilled a hole in the wall and installing a dowel or a wooden plug.

On combustible bases, it is recommended to install 2-3 mm thick asbestos gaskets on wooden socket boxes, which provide protection against fire in the socket if the contact connection in the switch or plug socket is faulty.

Wiring accessories are fixed on the socket with two round head screws (with the top cover removed). Then, pre-terminated wiring wires are connected to the terminals of the wiring product.

The switches are installed in the break of the phase wire going to the lamp holder. This allows you to quickly de-energize the power grid in the event of a short circuit and ensure electrical safety when replacing lamps and sockets. When installing the switches, you should pay attention to the fact that the electric lighting is turned on by pressing upper part keys or the top button of the switch.

The sockets are connected in parallel with the main wires of the electrical network.

The pre-ceiling switches have a metal base, they are attached directly to the wall without a socket outlet. The presence of cavities under the cover for placing wires allows you to dispense with a branch box.

With hidden wiring, switches and plug sockets are installed in metal or plastic boxes of the U-196, KP-1,2 types with a diameter of 69 mm and a height of 40 mm. The boxes are installed in recesses in the wall and fixed with alabaster mortar.

To fix the switch or power outlet in the box, remove the top decorative cover from them, attach the terminated wiring wires to the terminals, unscrew the screws from the spacer brackets so that you can push the switch or outlet into the box. When screwing in the screws, the tabs move apart and firmly fix the switch or the socket outlet in the box. The screws are screwed in all the way, alternately, avoiding skewing with such an effort so as not to split the base. After fixing the base of the switch (sockets), decorative covers are fixed to them.

Installation of luminaires

Artificial electric lighting in living quarters should provide normal hygienic conditions of visibility, the necessary comfort and coziness. To fulfill these conditions, general and combined lighting systems are used.

General lighting serves to illuminate the entire area of ​​the room.

Combined lighting is performed using general lighting lamps that provide the desired illumination throughout the room, and local lighting lamps create increased illumination in the workplace. Combined lighting is the most economical, allows you to create the best conditions for work and rest.

To distribute the luminous flux in the desired direction and protect it from glare, electric lamps are installed in the fittings. The lamp together with the fixture is called a luminaire.

The types of luminaires are selected depending on the nature of the environment, suspension height, lighting requirements and the interior of the room.

Depending on the type of light source, luminaires with incandescent lamps and fluorescent lamps are distinguished.

Incandescent lamps are light sources that work on the principle of thermal radiation. Incandescent light bulbs are by far the most common light source. In fig. 18 shows some types of incandescent lamps. As a filament in modern lamps, a spiral made of a refractory metal is used - most often of tungsten. The filament can be single-stranded or multi-stranded. Bulbs of incandescent lamps are evacuated or filled with a neutral gas (nitrogen, argon, krypton). The temperature of the heated filament reaches 2600–3000 ° C. The spectrum of incandescent lamps differs from the spectrum of daylight by the predominance of the yellow and red spectrum of the rays. The luminous efficiency of incandescent lamps, defined as the ratio of the power of the rays of the visible spectrum to the power consumed from the electrical network, is very small and does not exceed 3.5%.

Rice. 18. Some types of incandescent lamps: a - gas-filled; b - double spiral; c - bispiral krypton; g - mirror

The industry produces various types of lamps, differing in power and voltage ratings, sizes, bulb shapes, base materials and sizes, etc.

In the designation of incandescent lamps, the letters mean:

B - vacuum;

G - gas-filled;

B - double spiral;

BK - bispiral krypton;

DB - diffuse (with a matte reflective layer inside the bulb);

MO - local lighting, etc.

The number following the letter indicates the supply voltage, and the second indicates the lamp power in watts. Mirror lamps are produced with concentrated light distribution (ZK), medium (ZS), wide (ZSh), mirror lamps made of niodimum glass with concentrated or wide light distribution - ZKN, ZSHN. Mirror lamps are designed for lighting high rooms and open spaces, decorative lighting. Niodimium lamps are used where high quality color reproduction is required.

Decorative special lamps (D) can emit white (BL), yellow (W), green (W), red (K), opal (O) rays.

Incandescent lamps with a mirror reflector are produced - thermal emitters, quartz halogen (KG-220-1200; IKZK-220-500).

Incandescent lamp holders are divided into two main groups: threaded and pinned. In household lighting fixtures, as a rule, threaded sockets are used and are subdivided according to the size of the threaded sleeves - E14 - with a diameter of 14 mm (for minions), E27 - with a diameter of 27 mm, E40 - a diameter of 40 mm (lamp power more than 1.0 kW) ...

Cartridges are made from non-ferrous metals, steel, porcelain and plastics. According to the form of execution, the cartridges are divided into cartridges for screwing onto a nipple, cartridges with a flange and cartridges for suspension.

If the cartridge has a current-carrying screw sleeve, then the sleeve must be connected to the zero, and not to the phase conductor. This ensures electrical safety when replacing an electric lamp.

Electric lamps, in which electricity is converted into light directly, regardless of the thermal state of the substance, due to luminescence, are called luminescent.

The principle of operation of these lamps in a simplified representation is as follows. If a voltage is applied to the electrodes inserted into the ends of the glass tube, which is filled with a discharged inert gas or metal vapor, at the rate of at least 500-2000 V per 1 m of the tube length, then free electrons in the tube cavity begin to fly towards the electrode with a positive charge. When an alternating voltage is applied to the electrodes, the direction of movement of the electrons changes with the frequency of the current. In their motion, electrons meet with neutral gas atoms - filling the tube cavity and ionize them, knocking electrons out of the upper orbit into space or from the lower orbit to the upper one. The atoms excited in this way, once again colliding with electrons, again turn into neutral atoms. This reverse transformation is accompanied by the emission of a quantum of light energy. Each inert gas and metal vapor has its own spectral composition of the emitted light.

So, tubes with helium glow with light yellow or pale pink light, with neon - red light, with argon - blue, etc. By mixing inert gases or applying phosphors to the surface of the discharge tube, various shades of glow are obtained.

Fluorescent lamps of daylight and white light are made in the form of a straight or arched tube made of ordinary glass that does not transmit short ultraviolet rays. The electrodes are made from tungsten wire. The tube is filled with a mixture of argon and mercury vapor. The inside of the tube surface is covered with a phosphor - a special compound that glows under the influence of ultraviolet rays generated by an electric discharge in mercury vapor. Argon contributes to reliable combustion of the discharge in the tube.

The main advantage of fluorescent lamps in comparison with incandescent lamps is a higher efficiency (15–20%) and a 7-10 times longer service life.

Along with the positive qualities, fluorescent lamps also have disadvantages:

The complexity of the wiring diagram;

Dependence on ambient temperature; when the temperature drops, the lamps may go out or not light up;

Additional energy losses in the control gear, reaching 25–35% of the lamp power;

Luminous flux pulsations harmful to eyesight;

The presence of radio interference;

The light source and fixture form the luminaire. The armature redistributes the luminous flux in the desired direction, protects the light source from dust, moisture, etc. The luminaires are placed, whenever possible, in places that are convenient and safe for maintenance.

Lamps are charged with copper flexible wires with a cross-section of at least 0.5 mm 2 inside buildings and 1 mm 2 - for outdoor installation and are connected to the network wires using plug connectors or a chandelier clamp.

To decorate the place where the lamp is suspended, sometimes a ceiling lamp socket is used, inside which there is a chandelier clip. It is allowed to suspend the luminaire directly on the wires supplying it, provided that they are intended for this purpose.

Chandeliers, suspensions are hung on hooks (Fig. 19). Direct suspension of luminaires by wires is prohibited. The hook in the ceiling must be insulated from the chandelier, lamp with PVC tube. Hook insulation is necessary to prevent the appearance of a hazardous potential in the metal reinforcement of concrete slabs or steel pipes for electrical wiring if the insulation in the luminaire is broken. When attaching hooks to wooden floors hook isolation is not required. To install the hook, a hole is made in the hollow floor slab, and then the hook is fixed (Fig. 19 b). In solid reinforced concrete floors the luminaire is suspended from a hairpin, passed through the entire ceiling.

Rice. 19. Hooks for hanging lamps: a - on wooden ceilings; b - on hollow reinforced concrete slabs

All fixtures for suspension of luminaires are tested for strength with five times the mass of the luminaire. In this case, the suspension attachment parts must not have any damage or residual deformation.

Electrical wiring in cellars and basements

Cellars and basements, as a rule, are built from non-combustible materials and structures (brickwork, reinforced concrete blocks, ceilings, etc.). The floors are usually conductive, namely: earthen, concrete, from broken bricks, etc. Depending on the condition of the soil, ventilation efficiency, relative humidity, cellars and basements are damp and damp rooms, and according to the degree of danger of electric shock - to especially dangerous premises.

Increased requirements are imposed on electrical wiring in cellars and basements, namely:

The mains voltage should be not higher than 42 V. For this, step-down transformers should be used;

Carry out the electrical wiring directly on the base on insulators and rollers with insulated protected wires or cables. For hidden wiring, it is prohibited to use steel pipes with a wall thickness of 2 mm or less;

Luminaires of a sealed design should be used to prevent moisture from entering the electric cartridge;

The switch should be located outside the cellar and basement.

Wiring in attic spaces

An attic space is a room above the top floor of a building, the ceiling of which is the roof of the building and which has load-bearing structures (roof, truss, rafters, beams, etc.) made of combustible materials.

Electrical wiring in attics is performed mainly for laying the inputs from overhead lines into the building to the terminals of the apartment panel. In country houses, lighting of attics is not required.

It is better not to install any electrical wiring, apart from the gasket of inputs, in attics with structures made of combustible materials.

Attic spaces have a number of features. They are subject to temperature fluctuations, as a rule, they are dusty and have an increased fire hazard. Accidental damage to the electrical wiring can lead to a fire in wooden structures and subsequently to a fire. Therefore, increased requirements are imposed on electrical wiring in attics.

The following electrical wiring can be used in the attic:

Open - with wires and cables laid in steel pipes, as well as protected wires and cables in sheaths of non-combustible and non-combustible materials at any height;

Unprotected insulated single-core wires on rollers and insulators at a height of at least 2.5 m from the floor.

At a height of less than 2.5 m, they are protected from touch and mechanical damage. The distance between the attachment points of the rollers should be no more than 60 mm, insulators - no more than 1000 mm, between the wires - no less than 50 mm. The rollers must be at least 30 mm high. The rollers are installed on boards hemmed to the rafters.

Concealed electrical wiring is carried out in walls and ceilings made of non-combustible materials at any height.

Open electrical wiring in the attic is carried out with wires and cables with copper conductors. Wires and cables with aluminum conductors can be laid in buildings with fireproof ceilings, provided they are laid in steel pipes or hidden in fireproof walls and ceilings. Transit lines in attics up to 5 m long are allowed to be made with wires with aluminum conductors.

When laying steel pipes, it is necessary to exclude the penetration of dust into the pipes and junction boxes, for which sealed threaded connections are used. Pipes can only be connected using unsealed threaded couplings only in dry and dust-free attics.

Pipes are laid with a slope so that moisture cannot accumulate in them.

Connections and branches of copper or aluminum conductors of wires and cables are carried out in metal junction (branch) boxes by welding, crimping or using clamps corresponding to the material, cross-section and number of conductors.

Branches from the lines laid in the attic to electrical receivers installed outside the attics are allowed provided that both the line and the branches are laid openly in steel pipes, hidden in fireproof walls and ceilings.

Disconnecting devices in circuits supplying lamps located directly in attics are installed outside attics, for example, at the entrance to the attic.

Steel pipes, metal luminaire bodies and other metal structures of electrical wiring must be neutralized.

It is prohibited to lay any non-metallic pipes in attics.

Installation of apartment panels

The account of the consumed electricity and the settlement for it with the energy supplying organization is carried out according to the meter. The meter, as a rule, is mounted on the apartment panel along with the necessary switching and protective devices and devices. Mounting of meters on wooden, plastic or metal shields is allowed.

The industry produces single-phase and three-phase meters for various voltages and currents. The main types and characteristics of meters are given in tab. 16.

Table 16. Counters

In single-phase current circuits, active energy is measured by single-phase induction meters of direct switching (Fig. 20 a) or by switching through a current transformer (Fig. 20 b). When switched on via a current transformer, the meter readings are multiplied by the transformation ratio of the current transformer.

Rice. 20. Turning on a single-phase meter: a - single-phase direct-on meter; b - switching on a single-phase meter through a current transformer; G - generator clamps; Н - load clamps

In three-wire three-phase current circuits with uniform or uneven phase load, the energy is measured by two-element meters, for example, type SAZ-I670M or SAZ-I677 of direct connection (Fig. 21) or switched on through measuring current transformers (Fig. 22). The current transformers in both phases must have the same transformation ratio.

Rice. 21. Inclusion of three-phase meters SAZ-I677 and SAZ-I684 directly into a three-wire network

Rice. 22. Scheme of connection of SAZ-I670M and SAZ-I681 meters through current transformers into a three-wire network

Energy consumption is defined as the product of the meter reading by the transformation ratio of the current transformers and the transformation ratio of the voltage transformers, if applicable.

In a four-wire three-phase current network with a uniform and uneven load of the phases, energy can be counted using three single-phase meters, included as shown in Fig. 23, or using a three-element four-wire meter of type CA4 or CA4U (Fig. 24). When counted with three single-phase meters, the energy consumption is equal to the sum of the readings of all three meters, multiplied by the transformation ratio of the current transformers.

Rice. 23. Scheme of energy metering in a four-wire network with uneven phase load using three single-phase meters connected through current transformers

Rice. 24. Scheme of energy metering in a four-wire network with an uneven phase load using a three-phase CA4 meter for direct connection

In front of the meter, which is installed on the apartment panel, it is advisable to install a switch or a two-pole switch for safe meter replacement.

The load is necessarily connected to the meter through a protection device. Protective devices are used so that in the event of a malfunction of the internal wiring or an emergency overload of the network, it is automatically disconnected from the main line. For this purpose, fuses, circuit breakers or residual current devices are installed in the circuits of different wires of the network.

Disconnection should take place by breaking the line of the phase conductor. Therefore, fuses, as well as single-pole protective or switching devices, for example, A3161 or AB25 circuit breakers, are installed only in the phase conductor. Installation of these devices according to the PUE in the neutral wire is not allowed.

The neutral conductor line can only be broken simultaneously with the phase conductor line. This is ensured by two-pole switching or protection devices. A three-pole device can also be used, but with a single-phase (two-wire) input, one of the poles is not used.

In practice, it is common to install fuses in the line of not only the phase, but also the neutral wire, which contradicts the requirements of the current PUE.

The installation of fuses both in the phase conductor and in the zero conductor was justified by the unskilled operation of the apartment wiring. Indeed, if a fuse-link that had burned out in the line of one wire, in gross violation of the rules, was replaced with a wire jumper ("bug"), then protection was provided by a serviceable fuse in the line of the other wire. In addition, it was possible that in the wiring section before the fuses, the external difference between the phase and neutral wire will be lost. In this case, the presence of two fuses allows you to safely perform renovation work by unscrewing both plugs. Recall that initially, electrical energy in everyday life was used mainly in residential premises with non-conductive floors. Central heating was not yet common, and there were no piping or radiators in the rooms. Under these conditions, touching an electrical appliance with damaged insulation usually did not lead to electric shock, and grounding of the housings was not required as a means of increasing safety. Now the electrification of everyday life has gone beyond living rooms, and grounded heating, water supply and gas pipelines are increasingly encountered in rooms. This means that there is a possibility of being in contact with the ground or with a grounded metal object while using an electrical appliance. Under such conditions, damage to the insulation creates the risk of electric shock.

One of the means of ensuring safety is grounding, that is, the connection of metal non-current-carrying parts of electrical equipment with a grounded neutral wire. If a fuse or an automatic device is installed in the neutral wire circuit, then under certain conditions it can work and turn off the neutral wire, and this is tantamount to disabling the neutralization, which ensures the safety of the worker. Therefore, the installation of protective devices in the neutral wire in the presence of electrical appliances that require grounding is unacceptable.

Installation of the shield. Below is an example of how to install an apartment panel with fuses. The shield panel is punched out of steel or plastic with dimensions 360x170x27 mm. Fuses are placed in the upper part of the panel, a meter is installed under the fuses. The meter is secured with three screws. In the lower part of the panel under the counter there are four holes framed with plastic bushings for entering wires to the clamping device of the counter. The shield (Fig. 25) is mounted after completion of work on the installation of internal wiring in the house and entering the building from the overhead line.

Rice. 25. Connecting the apartment panel: 1 - input wires; 2 - disconnecting device; 3 - outgoing line screw; 4 - fuse; 5 - central contact screw; 6 - wire from meter to fuses; 7 - asbestos gasket; 8 - counter; 9 - shield body; 10 - wooden base

The shield is installed on a wall with a rigid structure, in places convenient for access and maintenance. It should be located away from the zone of possible mechanical stress (opening doors, shutters, etc.) and from heating pipelines, water supply, gas pipelines, no closer than 0.5 m.

The shield is attached to solid foundation strictly vertical with a slope of no more than 1 °. The distance from the floor to the terminal box of the meter should be within 0.8–1.7 m.

When installing an apartment shield in places where it can be damaged, for example, under stairs, the shield is placed in a cabinet with a window for a counter or in niches.

A fuse is one of the most common protection devices. For domestic consumption, fuses are designed as single-pole threaded fuses with E27 thread. The fuse consists of two main parts (Fig. 26 a): a rectangular base and a screw-in cylindrical body with a fusible insert. The base is installed on the shield in the phase conductor circuit. A wire coming from terminal (2) of the meter is connected to the terminal connected to the central contact; to the clamp of the threaded part - a wire going to the load. The fusible link is placed in a porcelain cylinder with two metal caps on the side of the ends. The insert is installed in a cylindrical body, which is screwed into the base.

Rice. 26. Electrical protection devices: a - PRS series fuse: 1 - fuse base; 2 - a screw-in cylindrical body with a fusible insert; b - automatic switch PAR-6,3 (PAR-10): 1 - power button; 2 - shutdown button

Fuse-links for fuses are available for a rated current of 6.3; ten; 16; 20 and 25 A.

Automatic switches. For use in apartment shields with fuse-links, automatic circuit breakers of the PAR type for 6.3 and 10 A with connecting dimensions, the same as the threaded fuses (Fig. 26 b). Unlike fuse-links, the circuit breaker is ready for operation again after tripping. To turn it on, just press the large diameter button, and by pressing the small diameter button, you can turn off the chain. These circuit breakers have a combined release: electromagnetic - for instantaneous disconnection of short circuits, and thermal - for disconnection of overloads.

Single-pole automatic switches A3161 or AB-25 with thermal releases for 15, 20 or 25 A, or AE1111 with combined releases for currents from 6.3 to 25 A.

At present, the industry produces introductory apartment shields of various modifications and types (SCHK, SCHO, SHKI, etc.)

The shields can be open or closed, respectively, for installation on a wall or in niches. They are equipped with fuses for one, two groups or single-pole circuit breakers for two or three groups. Panel dimensions - 260x150x129 mm. The machines and the counter are closed by a plastic case (cover) with a window for the counter and an opening for the control knobs of the machines. The cover is mounted on side latches and can be easily removed. The design of the shield allows the entry and exit of wires from above or below, the possibility of sealing them is provided.

It is advisable to power the main line of plug sockets and the lighting circuit from different fuses or circuit breakers. This achieves the preservation of lighting in the house during overload in the line of socket outlets.

Each installed settlement meter must have seals with the stamp of the state overseer on the screws securing the meter casing, and the seal of the power supply organization on the clamping cover.

Newly installed three-phase meters must have state verification seals no more than 12 months old, and single-phase meters - no more than 2 years old.

State meter verification is carried out once every 16 years.

Tools, fixtures, devices

When installing electrical wiring, a different tool is used in accordance with the type of work performed.

During installation wiring accessories and wiring, fitting tools are used: pliers, round-nose pliers, side cutters (diagonal cutters), a set of various screwdrivers, pliers for stripping insulation, scissors for cutting metal, a core, an awl, a knife, a soldering iron, etc. Some of the above are shown in Fig. ... 27.

Rice. 27. Electrician's tool

In the production of construction work for the laying of electrical wiring, hammers, sledgehammers, chisels, bolts of various diameters, drills, electric and hand drills, perforators, a set of drills with victorious solders, etc. are used.

For marking work, it is necessary to have plumb lines, a level, rulers, measuring tape 5-10 m, templates, compasses, vernier calipers, etc.

When working on connecting, branching and terminating wires and cables, use the KU-1 tongs, PK-1, PK-2M press tongs, cord tape brushes, gasoline blowtorches, soldering irons, etc.

To check the circuits during installation, you must have special devices.

The simplest is a conductivity tester, consisting of a battery, a light bulb and two wires (Fig. 28). To test the circuit, the tester is connected to the circuit under test using alligator clips. If the light is on, then the circuit is short-circuited, if the light goes out, the circuit is broken.

Rice. 28. The simplest conductivity tester

To measure the insulation resistance of the network, meggers of the M-4100/4 type are used, designed for a voltage of 400 V. The resistance of the grounding devices is checked with an M416 type device.

To determine the presence of voltage in the network, voltage indicators and indicators are used.

Single-pole voltage indicators UNN-1m, UNN-90, IN-90, IN-91 are designed to check the presence of voltage and determine phase wires in AC electrical installations when connecting electric meters, switches, lamp holders, fuses, etc.