Recently I did a project for the reconstruction of a boiler room and received a comment from the examination. The expert demanded that I show how I made the cable entry into the boiler building. Nothing complicated should arise here, but I would like to rely on any regulatory documents.

Now I will consider the two most common options for entering a cable into a building or cable structure. The choice of one or another type of cable entry depends on the specific conditions.

In this case, for each cable we provide a pipe, for example, asbestos-cement BNT-100. As a rule, cable networks up to 10 kV run at -0.7 m from ground level. Therefore, approximately at this level, the cables are entered into the building. It is allowed to enter cables at a depth of at least 0.5 m and not more than 2 m from the ground. When laying pipes, the pipe must be sloped towards the street at an angle of 0.5 degrees. After pulling the cables, all pipes are carefully sealed to prevent moisture and gas from entering the building. Inside the room, the pipe should go 50 mm. Outside, the length of the pipe depends on the blind area of ​​the building. On average, the length of the pipe is 1.5-2 m. As you can see from the figure, in some cases the pipe can reach up to 5 m. Just this option I had when connecting pumping station, which was in the embankment of the earth.

I use this option for entering cables into the building when entering power cables into the switchboard of a new building. Pipes are laid during the pouring of the foundation. At the same time, I also provide a pit for introducing pipes from the street, and I install an input-distribution device on this pit. The overall dimensions of the pit depend on the bending radius of the cable and overall dimensions ASU. Almost always I still lay one backup pipe.

It was this option that I provided to the expert, because. I had an existing building and it is not known what the foundation was there. According to the PUE, up to 2 m, we must protect all cables from mechanical damage. AT standard projects in this case cables are protected by casings. With small cross sections, I think it is better to lay cables in steel pipes. As a casing, you can take an unperforated metal tray. When leading the cable from the trench to the wall of the building, we need to break through only a small layer concrete blind area, while we do not touch the foundation.

This option is suitable for cable entry into existing buildings.

Regulatory documents for the entry of cables into the building:

1 TKP45-4.04-149-2009 (02250). Electrical equipment systems for residential and public buildings. Design rules (clause 16.1, 16.24).

2 SP 31-110-2003. Code of Practice for Design and Construction. "Design and installation of electrical installations of residential and public buildings" (clause 14.1, 14.24).

3 PUE 6. Rules for the installation of electrical installations (clause 2.1.58, 2.1.79, 2.3.32, 7.3.85).

4 Arch. No. 1.105.03tm. Laying power cables up to 10 kV in trenches (RB).

5 Code A5-92. Laying cables with voltage up to 35 kV in trenches. Issue 1 (RF).

Wiring. Scope, definitions

2.1.1. This chapter of the Rules applies to electrical wiring of power, lighting and secondary circuits voltage up to 1 kV AC and direct current performed inside buildings and structures, on their outer walls, on the territories of enterprises, institutions, microdistricts, yards, personal plots, on construction sites using insulated installation wires of all cross sections, as well as unarmoured 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 (for a cross section of more than 16 mm - see Ch. 2.3).

Lines performed by bare wires indoors must meet the requirements given in Ch. 2.2, outside buildings - in Ch. 2.4.

Branches from overhead lines to inputs (see 2.1.6 and 2.4.2), performed using insulated or bare wires, must be constructed in compliance with the requirements of Ch. 2.4, and branches performed using wires (cables) on a carrier cable - in accordance with the requirements of this chapter.

Cable lines laid directly in the ground must meet the requirements given in Ch. 2.3.

Additional requirements for electrical wiring are given in Ch. 1.5, 3.4, 5.4, 5.5 and in sec. 7.

2.1.2. Electrical wiring is a collection of wires and cables with their associated fixtures, supporting protective structures and parts installed in accordance with these Rules.

2.1.3. Cable, cord, protected wire, unprotected wire, special cable and wire - definitions according to GOST.

2.1.4. Wiring is divided into the following types:

1. Open wiring - laid on the surface of walls, ceilings, on trusses and other building elements of buildings and structures, on supports, etc.

With open wiring, the following methods of laying wires and cables are used: directly on the surface of walls, ceilings, etc., on strings, cables, rollers, insulators, in pipes, boxes, flexible metal sleeves, on trays, in electrical skirting boards and platbands, free suspension, etc.

Open wiring can be stationary, mobile and portable.

2. Concealed electrical wiring - laid inside the structural elements of buildings and structures (in walls, floors, foundations, ceilings), as well as along ceilings in floor preparation, directly under a removable floor, etc.

With hidden electrical wiring, the following methods of laying wires and cables are used: in pipes, flexible metal hoses, ducts, closed channels and voids in building structures, in plastered furrows, under plaster, as well as embedding in building structures during their manufacture.

2.1.5. External electrical wiring is electrical wiring laid along the outer walls of buildings and structures, under sheds, etc., as well as between buildings on supports (no more than four spans up to 25 m each) outside streets, roads, etc.

External wiring can be open and hidden.

2.1.6. An input from an overhead power line is an electrical wiring connecting a branch from an overhead line with an internal electrical wiring, counting from insulators installed on the outer surface (wall, roof) of a building or structure, to the terminals of the input device.

2.1.7. A string as a supporting element of electrical wiring is a steel wire stretched close to the surface of a wall, ceiling, etc., designed to attach wires, cables or their bundles to it.

2.1.8. A strip as a bearing element of electrical wiring is a metal strip fixed close to the surface of a wall, ceiling, etc., designed to attach wires, cables or their bundles to it.

2.1.9. A cable as a supporting element of electrical wiring is a steel wire or steel rope stretched in the air, designed to suspend wires, cables or their bundles to them.

2.1.10. A box is a closed hollow structure of a rectangular or other section, designed for laying wires and cables in it. The box should serve as protection against mechanical damage to the wires and cables laid in it.

Boxes can be blind or with opening lids, with solid or perforated walls and lids. Blind boxes should only have solid walls on all sides and not have lids.

The boxes can be used indoors and outdoors.

2.1.11. A tray is an open structure designed for laying wires and cables on it.

The tray is not a protection against external mechanical damage to the wires and cables laid on it. Trays must be made of non-combustible materials. They can be solid, perforated or lattice. Trays can be used indoors and outdoors.

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

Similar rooms and technical floors located directly above the roof, the ceilings and structures of which are made of fireproof materials, are not considered as attic rooms.

General requirements

2.1.13. Permissible continuous currents on wires and cables of electrical wiring should be taken according to Ch. 1.3 temperature sensitive environment and laying method.

2.1.14. The cross sections of the conductive cores of wires and cables in electrical wiring must be at least those given in Table. 2.1.1. The cross-sections of the conductors for charging lighting fixtures must be taken according to 6.5.12-6.5.14. The cross sections of grounding and zero protective conductors must be selected in compliance with the requirements of Ch. 1.7.

Table 2.1.1. The smallest sections of the conductive cores of wires and cables in electrical wiring

conductors	Cross-section of conductors, mm
		aluminum
Cords for connecting household electrical receivers
Cables for connecting portable and mobile power receivers in industrial installations
Twisted two-core wires with stranded conductors for fixed laying on rollers
Unprotected insulated wires for fixed indoor wiring:
directly on bases, on rollers, clips and cables
on trays, in boxes (except deaf ones):
single-wire
stranded (flexible)
on insulators
Unprotected insulated wires in outdoor wiring:
along walls, structures or supports on insulators;
overhead lines
under awnings on rollers
Unprotected and protected insulated wires and cables in pipes, metal sleeves and blind boxes
Cables and protected insulated wires for stationary electrical wiring (without pipes, sleeves and blind boxes):
for conductors connected to screw terminals
for cores connected by soldering:
single-wire
stranded (flexible)
Protected and unprotected wires and cables laid in closed channels or embedded (in building structures or under plaster)

2.1.15. Joint laying of wires and cables (with the exception of mutually reserved ones) is allowed in steel and other mechanical strong pipes, sleeves, boxes, trays and closed channels of building structures of buildings:

1. All circuits of one unit.

2. Power and control circuits of several machines, panels, panels, consoles, etc., connected by a technological process.

3. Circuits that feed a complex lamp.

4. Circuits of several groups of the same type of lighting (working or emergency) with total number no more than eight wires in the pipe.

5. Lighting circuits up to 42 V with circuits above 42 V, provided that the wires of the circuits up to 42 V are enclosed in a separate insulating tube.

2.1.16. Joint laying of mutually redundant circuits, circuits of working and emergency evacuation lighting, as well as circuits up to 42 V with circuits above 42 V is prohibited in one pipe, sleeve, box, bundle, closed channel of a building structure or on one tray (for an exception, see 2.1.15 , item 5 and in 6.1.16, item 1). The laying of these chains is allowed only in different compartments of boxes and trays that have continuous longitudinal partitions with a fire resistance limit of at least 0.25 hours from non-combustible material.

It is allowed to lay emergency (evacuation) and working lighting circuits on different outer sides of the profile (channel, angle, etc.).

2.1.17. In cable installations industrial premises and electrical rooms for electrical wiring should use wires and cables with sheaths only from slow-burning or non-combustible materials, and unprotected wires - with insulation only from slow-burning or non-combustible materials.

2.1.18. With alternating or rectified current, the laying of phase and neutral (or direct and reverse) conductors in steel pipes or insulating pipes with a steel sheath should be carried out in one common pipe.

It is allowed to lay the phase and neutral working (or direct and return) conductors in separate steel pipes or in insulating pipes with a steel sheath, if the continuous load current in the conductors does not exceed 25 A.

2.1.19. When laying wires and cables in pipes, blind boxes, flexible metal sleeves and closed channels, it should be possible to replace wires and cables.

2.1.20. Structural elements of buildings and structures, closed channels and voids of which are used for laying wires and cables, must be fireproof.

2.1.21. Connection, branching and termination of conductors of wires and cables must be carried out by crimping, welding, soldering or clamping (screw, bolt, etc.) in accordance with the current instructions approved in the prescribed manner.

2.1.22. In places of connection, branching and connection of cores of wires or cables, a reserve of wire (cable) must be provided, which ensures the possibility of reconnection, branching or connection.

2.1.23. Connection points and branches of wires and cables must be accessible for inspection and repair.

2.1.24. At the junctions and branches, wires and cables should not experience mechanical tensile forces.

2.1.25. The places of connection and branching of the cores of wires and cables, as well as connecting and branch clamps, etc., must have insulation equivalent to the insulation of the cores of the entire places of these wires and cables.

2.1.26. Connection and branching of wires and cables, with the exception of wires laid on insulating supports, must be carried out in junction and junction boxes, in insulating cases of junction and branch clamps, in special niches of building structures, inside cases wiring accessories, devices and machines. When laying on insulating supports, the connection or branching of the wires should be carried out directly at the insulator, the clamp or on them, as well as on the roller.

2.1.27. The design of junction and branch boxes and clamps must comply with the laying methods and environmental conditions.

2.1.28. Junction and junction boxes and insulating housings of junction and junction clamps should, as a rule, be made of non-combustible or slow-burning materials.

2.1.29. Metal elements of electrical wiring (structures, boxes, trays, pipes, sleeves, boxes, brackets, etc.) must be protected from corrosion in accordance with environmental conditions.

2.1.30. Electrical wiring must be made taking into account their possible movements at the intersections with temperature and sedimentary seams.

The choice of the type of electrical wiring, the choice of wires and cables and the way they are laid

2.1.31. Electrical wiring must comply with environmental conditions, the purpose and value of structures, their design and architectural features. Wiring should be easy to recognize along the entire length of the conductors by colors:

blue color - to designate the zero working or middle conductor of the electrical network;

a two-color combination of green-yellow color - to designate a protective or neutral protective conductor;

a two-color combination of green-yellow color along the entire length with blue marks at the ends of the line, which are applied during installation - to indicate the combined zero working and zero protective conductor;

black, brown, red, purple, grey, pink, white, orange, turquoise color- to designate a phase conductor.

2.1.32. When choosing the type of electrical wiring and the method of laying wires and cables, electrical safety requirements and fire safety.

2.1.33. The choice of types of electrical wiring, the choice of wires and cables and the method of their laying should be carried out in accordance with Table. 2.1.2.

If there are two or more conditions that characterize the environment at the same time, the electrical wiring must comply with all these conditions.

2.1.34. Sheaths and insulation of wires and cables used in electrical wiring must comply with the laying method and environmental conditions. The insulation must also match the rated mains voltage.

If there are special requirements due to the characteristics of the installation, the insulation of wires and the protective sheaths of wires and cables must be selected taking into account these requirements (see also 2.1.50 and 2.1.51).

2.1.35. Zero working conductors must have insulation equivalent to that of the phase conductors.

In production normal rooms it is allowed to use steel pipes and cables of open electrical wiring, as well as metal cases openly installed conductors, metal structures buildings, industrial structures (for example, trusses, columns, crane tracks) and mechanisms as one of the working conductors of the line in networks with voltage up to 42 V. At the same time, continuity and sufficient conductivity of these conductors, visibility and reliable welding of joints must be ensured.

The use of the above structures as a working conductor is not allowed if the structures are in close proximity to combustible parts of buildings or structures.

2.1.36. The laying of wires and cables, pipes and ducts with wires and cables, according to fire safety conditions, must meet the requirements of Table. 2.1.3.

2.1.37. During open laying of protected wires (cables) with sheaths of combustible materials and unprotected wires, the clear distance from the wire (cable) to the surface of bases, structures, parts made of combustible materials must be at least 10 mm. If it is impossible to provide the specified distance, the wire (cable) should be separated from the surface by a layer of fireproof material protruding from each side of the wire (cable) by at least 10 mm.

2.1.38. At hidden gasket protected wires (cables) with sheaths of combustible materials and unprotected wires in closed niches, in the voids of building structures (for example, between the wall and the cladding), in furrows, etc. with the presence of combustible structures, it is necessary to protect wires and cables with a continuous layer of fireproof material from all sides.

2.1.39. In case of open laying of pipes and ducts made of slow-burning materials on non-combustible and slow-burning bases and structures, the clear distance from the pipe (duct) to the surface of structures, parts made of combustible materials should be at least 100 mm. If it is impossible to provide the specified distance, the pipe (box) should be separated on all sides from these surfaces with a continuous layer of fireproof material (plaster, alabaster, cement mortar, concrete, etc.) with a thickness of at least 10 mm.

2.1.40. In case of hidden laying of pipes and ducts made of slow-burning materials in closed niches, in the voids of building structures (for example, between a wall and lining), in furrows, etc., pipes and ducts should be separated from all sides from the surfaces of structures, parts made of combustible materials with a solid a layer of fireproof material with a thickness of at least 10 mm.

2.1.41. When crossing short sections of electrical wiring with elements of building structures made of combustible materials, these sections must be made in compliance with the requirements of 2.1.36-2.1.40.

2.1.42. In places where, due to high ambient temperature, the use of wires and cables with insulation and sheaths of normal heat resistance is impossible or leads to an unreasonable increase in the consumption of non-ferrous metal, wires and cables with insulation and sheaths of increased heat resistance should be used.

2.1.43. In damp and especially damp rooms and outdoor installations, wire insulation and insulating supports, as well as supporting and supporting structures, pipes, ducts and trays must be moisture resistant.

2.1.45. In rooms and outdoor installations with a chemically active environment, all electrical wiring elements must be resistant to the environment or protected from its effects.

2.1.46. Wires and cables with non-light-resistant outer insulation or sheath must be protected from direct rays.

2.1.47. In places where mechanical damage to electrical wiring is possible, openly laid wires and cables must be protected from them by their protective sheaths, and if such sheaths are absent or not sufficiently resistant to mechanical stress, by pipes, boxes, fences or the use of hidden electrical wiring.

2.1.48. Wires and cables should be used only in those areas that are specified in the standards and specifications for cables (wires).

2.1.49. For stationary electrical wiring, mainly wires and cables with aluminum conductors should be used. For exceptions see 2.1.70, 3.4.3, 3.4.12, 5.5.6, 6.5.12-6.5.14, 7.2.53 and 7.3.93.

Table 2.1.2. The choice of types of electrical wiring, laying methods and wires and cables

Environmental conditions	Type of wiring and laying method	Wires and cables
Exposed electrical wiring
Dry and wet areas	On roller skates and clicks
Dry rooms		Twisted two-wire wires
	On insulators, as well as on rollers intended for use in damp places. In outdoor installations rollers for wet areas ( large sizes) is allowed to be used only in places where the possibility of direct rain or snow on the electrical wiring is excluded (under awnings)	Bare solid wires
outdoor installations	Directly on the surface of walls, ceilings and on strings, strips and other load-bearing structures	Cable in non-metallic and metal sheaths
Premises of all kinds		Unprotected and protected solid and stranded wires. Cables in non-metallic and metallic sheaths
Premises of all kinds and outdoor installations	On trays and in boxes with opening lids
Premises of all kinds and outdoor installations (only special wires with support cable for outdoor installations or cables)	On ropes	Special wires with carrying cable. Unprotected and protected solid and stranded wires. Cables in non-metallic and metallic sheaths
Hidden wiring
Premises of all kinds and outdoor installations	In non-metallic pipes made of combustible materials (non-self-extinguishing polyethylene, etc.). In closed channels of building structures. under plaster	Unprotected and protected, solid and stranded wires. Cables in non-metallic sheath
	Exceptions:
Dry, wet and damp areas	Embedded in building structures during their manufacture	Bare wires
Open and hidden electrical wiring
Premises of all kinds and outdoor installations	In metal flexible sleeves. In steel pipes (ordinary and thin-walled) and deaf steel boxes. In non-metallic pipes and non-metallic blind boxes made of slow-burning materials. In insulating pipes with a metal sheath	Unprotected and protected solid and stranded wires. Cables in non-metallic sheath
	Exceptions:
	1. It is forbidden to use insulating pipes with a metal sheath in damp, especially damp rooms and outdoor installations
	2. It is forbidden to use steel pipes and steel blind boxes with a wall thickness of 2 mm or less in damp, especially damp rooms and outdoor installations.

Table 2.1.3. The choice of types of electrical wiring and methods of laying wires and cables according to fire safety conditions

Type of electrical wiring and method of laying on bases and structures
from combustible materials	from non-combustible or slow-burning materials	Wires and cables
Exposed electrical wiring
On casters, insulators or lined with fireproof materials	Directly
Directly	Directly	Sheathed wires and cables sheathed from non-combustible and slow-burning materials
In pipes and boxes made of non-combustible materials	In pipes and boxes made of slow-burning and non-combustible materials	Unprotected and protected wires and cables sheathed from combustible, slow-burning materials
Hidden wiring
With a lining of fireproof materials and subsequent plastering or protection on all sides with a continuous layer of other fireproof materials	Directly	Unprotected wires; sheathed wires and cables sheathed with combustible materials
Lined with fireproof materials	Directly	Sheathed wires and cables sheathed with flame retardant materials
Directly	Directly	The same from non-combustible
In pipes and ducts made of fire-retardant materials - with a lining for pipes and ducts of fireproof materials and subsequent plastering	In pipes and ducts: from combustible materials - embedded, in furrows, etc., in a continuous layer of fireproof materials	Unprotected wires and cables sheathed with combustible, slow-burning and non-combustible materials
The same from fireproof materials - directly	The same from slow-burning and fireproof materials - directly

The lining of non-combustible materials must protrude from each side of the wire, cable, pipe or conduit by at least 10 mm.
The plastering of the pipe is carried out with a continuous layer of plaster, alabaster, etc. with a thickness of at least 10 mm above the pipe.
A continuous layer of fireproof material around the pipe (box) can be a layer of plaster, alabaster, cement mortar or concrete with a minimum thickness of 10 mm.

It is not allowed to use wires and cables with aluminum conductors for connection to electrical devices installed directly on vibration isolating supports.

In museums, art galleries, libraries, archives and other repositories of national importance, only wires and cables with copper conductors should be used.

2.1.50. To power portable and mobile electrical receivers, cords and flexible cables with copper conductors, specially designed for this purpose, should be used, taking into account possible mechanical effects. All cores of the specified conductors, including the grounding conductor, must be in a common sheath, braid or have a common insulation.

For mechanisms with limited movement (cranes, mobile saws, gate mechanisms, etc.), it is necessary to use such current duct designs that protect the cores of wires and cables from breaking (for example, flexible cable loops, carriages for movable suspension of flexible cables).

2.1.51. In the presence of oils and emulsions in the places where the wires are laid, wires with oil-resistant insulation should be used or the wires should be protected from their effects.

Exposed electrical wiring inside the premises

2.1.52. Open laying of unprotected insulated wires directly on the bases, on rollers, insulators, on cables and trays should be carried out:

1. At voltages above 42 V in rooms without increased danger and at voltages up to 42 V in any rooms - at a height of at least 2 m from the floor level or service platform.

2. At voltages above 42 V in areas with increased danger and especially dangerous - at a height of at least 2.5 m from the floor level or service platform.

These requirements do not apply to descents to switches, sockets, starting devices, shields, wall-mounted lamps.

In industrial premises, the descents of unprotected wires to switches, sockets, devices, shields, etc. must be protected from mechanical influences up to a height of at least 1.5 m from the floor level or service platform.

In domestic premises of industrial enterprises, in residential and public buildings, these slopes may not be protected from mechanical influences.

In rooms accessible only to specially trained personnel, the height of openly laid unprotected insulated wires is not standardized.

2.1.53. In crane spans, unprotected insulated wires should be laid at a height of at least 2.5 m from the level of the crane trolley platform (if the platform is located above the crane bridge deck) or from the crane bridge deck (if the deck is located above the trolley platform). If this is not possible, then protective devices must be provided to protect the personnel on the trolley and crane bridge from accidentally touching the wires. A protective device must be installed along the entire length of the wires or on the crane bridge itself within the location of the wires.

2.1.54. The height of the open laying of protected insulated wires, cables, as well as wires and cables in pipes, boxes with a degree of protection of at least IP20, in flexible metal hoses from the floor level or service platform is not standardized.

2.1.55. If unprotected insulated wires intersect with unprotected or protected insulated wires with a distance between the wires of less than 10 mm, then additional insulation must be applied to each unprotected wire at the intersection.

2.1.56. When crossing unprotected and protected wires and cables with pipelines, the clear distances between them must be at least 50 mm, and with pipelines containing flammable or flammable liquids and gases, at least 100 mm. If the distance from wires and cables to pipelines is less than 250 mm, wires and cables must be additionally protected from mechanical damage at a length of at least 250 mm on each side of the pipeline.

When crossing hot pipelines, wires and cables must be protected from high temperatures or must be designed accordingly.

2.1.57. When laying in parallel, the distance from wires and cables to pipelines must be at least 100 mm, and to pipelines with flammable or flammable liquids and gases - at least 400 mm.

Wires and cables laid parallel to hot pipelines must be protected from high temperatures or must be of an appropriate design.

2.1.58. In places where wires and cables pass through walls, interfloor ceilings or exit to the outside, it is necessary to provide the possibility of changing the electrical wiring. To do this, the passage must be made in a pipe, duct, opening, etc. In order to prevent the penetration and accumulation of water and the spread of fire in places of passage through walls, ceilings or exits to the outside, gaps between wires, cables and a pipe (duct, opening etc.), as well as reserve pipes (ducts, openings, etc.) with an easily removed mass from fireproof material. The seal must allow replacement, additional laying of new wires and cables and ensure the fire resistance of the opening is not less than the fire resistance of the wall (ceiling).

2.1.59. When laying unprotected wires on insulating supports, the wires must be additionally insulated (for example, with an insulating pipe) at the points of passage through walls or ceilings. When these wires pass from one dry or wet room to another dry or wet room, all wires of one line can be laid in one insulating pipe.

When passing wires from a dry or damp room to a damp one, from one damp room to another damp or when the wires come out of the room to the outside, each wire must be laid in a separate insulating pipe. When exiting a dry or damp room into a damp or outside building, wire connections must be made in a dry or damp room.

2.1.60. On trays, supporting surfaces, cables, strings, strips and other supporting structures, it is allowed to lay wires and cables close to each other in bundles (groups) various shapes(for example, round, rectangular in several layers).

The wires and cables of each bundle must be fastened together.

2.1.61. In ducts, wires and cables are allowed to be laid in layers with an ordered and arbitrary (loose) mutual arrangement. The sum of cross sections of wires and cables, calculated according to their outer diameters, including insulation and outer sheaths, should not exceed: for deaf ducts 35% of the duct cross section in the light; for boxes with opening lids 40%.

2.1.62. Permissible long-term currents for wires and cables laid in bundles (groups) or multilayer should be taken into account with reduction factors that take into account the number and location of conductors (cores) in the bundle, the number and mutual arrangement bundles (layers), as well as the presence of unloaded conductors.

2.1.63. Pipes, boxes and flexible metal sleeves of electrical wiring must be laid in such a way that moisture cannot accumulate in them, including from the condensation of vapors contained in the air.

2.1.64. In dry, dust-free rooms, in which there are no vapors and gases that adversely affect the insulation and sheath of wires and cables, it is allowed to connect pipes, ducts and flexible metal hoses without sealing.

The connection of pipes, ducts and flexible metal hoses with each other, as well as with ducts, electrical equipment cases, etc., must be performed:

in rooms that contain vapors or gases that adversely affect the insulation or sheaths of wires and cables, in outdoor installations and in places where oil, water or emulsion can get into pipes, boxes and sleeves - with a seal; the boxes in these cases should be with solid walls and sealed with solid covers or deaf, split boxes - with seals at the split points, and flexible metal sleeves - sealed;

in dusty rooms - with sealing of joints and branches of pipes, sleeves and ducts to protect against dust.

2.1.65. The connection of steel pipes and ducts used as grounding or zero protective conductors must comply with the requirements given in this chapter and Ch. 1.7.

Hidden electrical wiring inside the premises

2.1.66. Hidden electrical wiring in pipes, ducts and flexible metal hoses must be made in compliance with the requirements given in 2.1.63-2.1.65, and in all cases - with a seal. The box of hidden electrical wiring must be deaf.

2.1.67. Performing electrical wiring in ventilation ducts and mines is prohibited. It is allowed to cross these channels and shafts with single wires and cables enclosed in steel pipes.

2.1.68. Laying wires and cables suspended ceilings should be carried out in accordance with the requirements of this chapter and Ch. 7.1.

Wiring in the attic

2.1.69. AT attic spaces The following types of wiring can be used:

open;

wires and cables laid in pipes, as well as protected wires and cables in sheaths made of fireproof or slow-burning materials - at any height;

unprotected insulated single-core wires on rollers or insulators (in the attic of industrial buildings - only on insulators) - at a height of at least 2.5 m; if the height to the wires is less than 2.5 m, they must be protected from touch and mechanical damage;

hidden: in walls and ceilings made of non-combustible materials - at any height.

2.1.70. Open electrical wiring in the attic should be carried out with wires and cables with copper conductors.

Wires and cables with aluminum conductors are allowed in attic spaces: buildings with fireproof ceilings - when they are laid open in steel pipes or hidden in fireproof walls and ceilings; industrial buildings for agricultural purposes with combustible ceilings - when they are laid open in steel pipes with the exception of dust penetration into the pipes and junction (branch) boxes; threaded connections must be used.

2.1.71. The connection and branching of copper or aluminum cores of wires and cables in attic spaces should be carried out in metal junction (branch) boxes by welding, crimping or using clamps corresponding to the material, cross section and number of cores.

2.1.72. Electrical wiring in attic spaces made using steel pipes must also meet the requirements given in 2.1.63-2.1.65.

2.1.73. Branches from lines laid in the attic to electrical receivers installed outside the attics are allowed provided that the lines and branches are laid openly in steel pipes or hidden in fireproof walls (ceilings).

2.1.74. Switching devices in the circuits of lamps and other electrical receivers installed directly in attic spaces must be installed outside these premises.

External wiring

When hanging wires on supports near buildings, the distance from the wires to balconies and windows must be at least 1.5 m with a maximum deviation of the wires.

External wiring on the roofs of residential, public buildings and entertainment enterprises is not allowed, with the exception of inputs to buildings (enterprises) and branches to these inputs (see 2.1.79).

Unprotected insulated wires of external wiring should be considered as uninsulated with respect to contact.

2.1.76. Distances from wires crossing fire passages and ways for transporting goods to the surface of the earth (road) in the carriageway must be at least 6 m, in the impassable part - at least 3.5 m.

2.1.77. The distances between the wires should be: with a span of up to 6 m - at least 0.1 m, with a span of more than 6 m - at least 0.15 m. The distances from the wires to the walls and supporting structures must be at least 50 mm.

2.1.78. Laying of wires and cables of external electrical wiring in pipes, ducts and flexible metal hoses must be carried out in accordance with the requirements given in 2.1.63-2.1.65, and in all cases with a seal. Laying wires in steel pipes and ducts in the ground outside buildings is not allowed.

The distance from the wires in front of the input and the input wires to the ground surface must be at least 2.75 m (see also 2.4.37 and 2.4.56).

The distance between the wires at the input insulators, as well as from the wires to the protruding parts of the building (roof overhangs, etc.) must be at least 0.2 m.

Entries are allowed to be made through roofs in steel pipes. In this case, the vertical distance from the branch wires to the input and from the input wires to the roof must be at least 2.5 m.

For low height buildings trade pavilions, kiosks, container-type buildings, mobile booths, vans, etc.), on the roofs of which people are excluded, the clear distance from the branch wires to the input and the input wires to the roof is allowed to be at least 0.5 m. In this case, the distance from the wires to the ground surface must be at least 2.75 m.

Page 13 of 52

CABLE LINES

General requirements

3.56. These rules should be observed when installing power cable lines with voltage up to 220 kV.

Installation of cable lines of the subway, mines, mines should be carried out taking into account the requirements of the VSN, approved in the manner established by SNiP 1.01.01-82.

3.57. The smallest permissible bending radii of cables and the permissible level difference between the highest and lowest points of the location of cables with impregnated paper insulation on the route must comply with the requirements of GOST 24183-80 *, GOST 16441-78, GOST 24334-80. GOST 1508-78* E and approved specifications.

3.58. When laying cables, measures should be taken to protect them from mechanical damage. The tensile forces of cables up to 35 kV must be within the values ​​\u200b\u200bgiven in Table. 3. Winches and other traction means must be equipped with adjustable limiting devices to turn off the tension when forces appear above the allowable ones. Pulling devices that compress the cable (drive rollers), as well as rotary devices, must exclude the possibility of cable deformation.

For cables with a voltage of 110-220 kV, the permissible tensile forces are given in clause 3.100.

3.59. Cables should be laid with a margin of 1-2% in length. In trenches and on solid surfaces inside buildings and structures, the margin is achieved by laying the cable in a "snake" and, along cable structures (brackets), this margin is used to form a sag.

Laying the cable stock in the form of rings (turns) is not allowed.

Table3

	Pulling force for			Tension forces for the cores, kN, cable up to 35, kV
Cable section, mm 2	aluminum sheath, kN, cable voltage, kV			copper	aluminum stranded	aluminum single-wire
	1,7 1,8 2,3 2,9 3,4 3,9 5,9 6,4 7,4	2,8 2,9 3,4 3,9 4,4 4,9 6,4 7,4 9,3	3,7 3,9 4,4 4,9 5,7 6,4 7,4 8,3 9,8

* Made of soft aluminum with a relative elongation of not more than 30%. Notes: 1. Pulling a cable with a plastic or lead sheath is allowed only by the cores.

2. The tensile forces of the cable when pulling it through the block sewer are given in Table. four.

3. Cables armored with round wire should be pulled by the wires. Permissible stress 70-100 N/mm 2 .

4. Control cables both armored and unarmored power cables with a cross section of up to 3 x 16 mm 2, in contrast to the cables of large cross sections given in this table, it is allowed to lay mechanically by pulling behind the armor or behind the sheath using a wire stocking, the pulling forces should not exceed 1 kN.

3.60. Cables laid horizontally along structures, walls, ceilings, trusses, etc., should be rigidly fixed at the end points, directly at the end sleeves, at the turns of the route, on both sides of the bends and at the connecting and locking sleeves.

3.61. Cables laid vertically along structures and walls must be fixed to each cable structure.

3.62. The distances between the supporting structures are taken in accordance with the working drawings. When laying power and control cables with an aluminum sheath on supporting structures with a distance of 6000 mm, a residual deflection in the middle of the span must be ensured: 250-300 mm when laying on overpasses and galleries, at least 100-150 mm in other cable structures.

Structures on which unarmored cables are laid must be of a design that excludes the possibility of mechanical damage to the cable sheaths.

In places of rigid fastening of unarmored cables with a lead or aluminum sheath, gaskets made of elastic material (for example, rubber sheet, polyvinyl chloride sheet) must be laid on the structures; unarmored cables with a plastic sheath or plastic hose, as well as armored cables, can be fastened to structures with brackets (clamps) without gaskets.

3.63. Armored and unarmored cables indoors and outdoors in places where mechanical damage is possible (movement of vehicles, cargo and mechanisms, accessibility for unqualified personnel) must be protected to a safe height, but not less than 2 m from the ground or floor level and at a depth of 0.3 m in the ground.

3.64. The ends of all cables in which the sealing is broken during the laying process must be temporarily sealed before the installation of connecting and termination couplings.

3.65. Cable passages through walls, partitions and ceilings in industrial premises and cable structures must be carried out through segments of non-metallic pipes (non-pressure asbestos, plastic, etc.), textured holes in reinforced concrete structures or open openings. Gaps in pipe sections, holes and openings after laying cables must be sealed with fireproof material, for example, cement with sand by volume 1:10, clay with sand - 1:3, clay with cement and sand - 1.5:1:11 , perlite expanded with building plaster- 1:2, etc., over the entire thickness of the wall or partition.

Gaps in passages through walls may not be sealed if these walls are not fire barriers.

3.66. The trench before laying the cable should be inspected to identify places on the route containing substances that have a destructive effect on the metal cover and cable sheath (salt marshes, lime, water, bulk soil containing slag or construction waste, areas located closer than 2 m from cesspools and garbage pits, etc.). If it is not possible to bypass these places, the cable must be laid in clean neutral ground in non-pressure asbestos-cement pipes ah, covered outside and inside with a bitumen composition, etc. When filling the cable with neutral soil, the trench should be further expanded on both sides by 0.5-0.6 m and deepened by 0.3-0.4 m.

3.67. Cable entries into buildings, cable structures and other premises must be made in asbestos-cement non-pressure pipes in textured holes reinforced concrete structures The ends of the pipes should protrude from the wall of the building into the trench, and if there is a blind area, beyond the line of the latter by at least 0.6 m and have a slope towards the trench.

3.68. When laying several cables in a trench, the ends of the cables. intended for the subsequent installation of connecting and locking couplings, should be located with a shift in the connection points of at least 2 m. end not less than 350 mm for cables with voltage up to 10 kV and not less than 400 mm for cables with voltage 20 and 35 kV).

3.69. In cramped conditions with large cable flows, it is allowed to place expansion joints in a vertical plane below the cable laying level. The sleeve remains at the level of the cable routing.

3.70. The cable laid in the trench should be sprinkled with the first layer of earth, mechanical protection or signal tape should be laid, after which representatives of the electrical installation and construction organizations, together with the representative of the customer, should inspect the route with drawing up an act for hidden work.

3.71. The trench must be finally backfilled and compacted after the installation of the couplings and testing the line with increased voltage.

3.72. Backfilling the trench with clods of frozen earth, soil containing stones, pieces of metal, etc., is not allowed.

3.73. Trenchless laying from a self-propelled or traction-driven knife cable layer is allowed for 1-2 armored cables with a voltage of up to 10 kV with a lead or aluminum sheath on cable routes remote from engineering structures. In urban power grids and industrial enterprises trenchless laying is allowed only on long sections in the absence of underground utilities, intersections with engineering structures, natural obstacles and hard surfaces on the route.

3.74. When laying a route cable line in undeveloped areas along the entire route, identification marks should be installed on concrete columns or on special signposts, which are placed at the turns of the route, at the locations of couplings, on both sides of intersections with roads and underground structures, at building entrances and every 100 m on straight sections.

On the arable land Identification signs should be installed at least every 500 m.

Content

Cable entry to the network node (NC), terminal and intermediate points, to the buildings of the PBX and other communication enterprises is carried out through specially equipped cable entry rooms, located, as a rule, in the basement (basement) room, and in buildings without a basement - on the first floor with a pit device in the floor of the room.

The following basic requirements are imposed on cable entry rooms and compressor rooms (to accommodate equipment for maintaining cables under excessive air pressure):

- the room for the entry of communication cables and the compressor room should be located in separate rooms, which should be adjacent;

- the location of the premises and their bads are taken depending on the composition of the equipment and the number of input cables;

- entrances to the cable entry rooms and compressor rooms should be provided separately;

- the height of the cable entry rooms should be at least 3.5 m from the floor to the bottom of the protruding part of the ceiling with a vertical location of branching sleeves (gloves), with their horizontal location, the height of the cable entry rooms should be at least 2.5 m. (console) is prohibited;

- in the cable entry and compressor rooms, floors should be cement-sand with iron, walls and ceiling - painted with water-based paint;

- the normative temporary distribution surface load on the floor is accepted: in the cable entry rooms - long-term 5600 Pa (560 kgf / m 2), short-term 900 Pa (90 kgf / m 2), and in compressor rooms - long-term and short-term 1000 Pa;

- in communication vertical shafts, joint laying of a communication cable with power and control cables is not allowed.

Cable entry example outer wall EC is shown in Figures 2.9, 2.10.

Cable entry should be carried out taking into account their minimum length inside buildings, permissible bending radii, maximum use of existing metal structures, as well as ease of use.

To enter cables into the opening of the foundation or wall of the building of the PBX, OMS, an inlet block of asbestos-cement (concrete) pipes with an internal diameter of channels of 100 mm should be laid. The block capacity is determined by the project depending on the number of input cables, taking into account spare channels for development (at least 100% of the channels occupied by linear cables according to the project).

The inlet block of asbestos-cement pipes at the entrance to the cable entry room must be recessed into the foundation of the building and carefully concreted with concrete grade 200. All free space between individual pipes, as well as between pipes and the foundation of the building, must be filled with concrete.

The use of polyethylene pipes for cable entry is not allowed.

The inlet block of asbestos-cement pipes in the buildings of ground-based communication enterprises should, as a rule, end with an inlet station cable well located near the building, but no further than 30 m from it. The standard size of the station well is determined by the capacity of the inlet block of cable duct pipes.

The bottom row of the pipe inlet block must be at least 0.2 m above the floor level of the cable entry room. The inlet collector or pipeline must have a slope towards the station well.

All channels of the input units, both free and occupied by cables in the buildings of the automatic telephone exchange and OMS, must be hermetically sealed from the side of the cable entry room using sealing devices.

Buildings in which the number of designed subscriber devices is more than three should be equipped with cable glands. In buildings with less than three subscribers, subscriber devices should be connected to cable boxes installed on overhead line poles or in attics under racks.

Underground cable entries to buildings should be provided through cable duct blocks, semi-through collectors, technical undergrounds and basements. At the same time, inside buildings, cables should be laid through hidden channels and included in junction boxes installed in special cabinets and niches.

Figure 2.9 –

Figure 2.10 – Scheme of the input of the fiber optic cable on the outer wall of the EC post

In exceptional cases, in the absence of hidden channels, technical subfloors or basements in buildings, the cable should be introduced into buildings open way along the side or internal (yard) walls of buildings.

In buildings located inside blocks, cable entries should be arranged using cable duct jumpers from other buildings in the block or use intra-block collectors of small cross section. With a length of cable duct jumpers up to 30 m, wells are not installed, and with a length of 30 m or more, a KKS-2 well should be provided at one of the inputs.

The development of design solutions for the introduction of cables into the technical buildings of communication enterprises should be carried out taking into account the following:

- ensuring the minimum length of their laying inside the premises;

- the least number of bends;

– ensuring acceptable cable bending radii;

- maximum use of existing lead-in and cable equipment;

– existing devices for keeping cables under constant excess air pressure and metal structures.

The node diagram is shown in Figure 2.11.

Figure 2.11– Node diagram

In cable entry rooms, it is necessary to provide a set of metal structures, consisting, as a rule, of various supporting structures, air cable gutters and consoles, as well as standard non-standard products that provide the possibility of laying line and distribution cables, installing UOC, boxes, as well as direct connecting, insulating , gas-tight and branching cable joints.

Cable entry into the buildings of telephone exchanges must be provided by underground cables.

When equipping the inputs of electrical and optical cables into the technical buildings of communication enterprises, fire safety conditions should be provided:

- line and distribution electric cables should be provided, if possible, with an outer protective sheath that does not propagate combustion.

The laying of linear fiber optic cables from the cable entry room to the LAZ to the installation sites of the optical cross-connect and SBS, as well as the station optical cables from OK and SBS to the OLT racks, as a rule, should be carried out at cable racks in separate packages.

Linear and distribution cables carrying DP in the areas from the entrance to the building to the input equipment should be laid on separate air ducts (at newly designed facilities) and separately along existing chutes or in the same packages with existing cables carrying DP.

When entering all types of cables into subway tunnels, the installation of electrically insulating sleeves should be provided. The places of their installation on the cables are determined by the project.

The inputs of pipelines with fiber-optic cables into service buildings should be carried out separately from the inputs of power supply cables and cables of signaling devices.

It is necessary to ensure the tightness of inlet channels with pipelines, as well as reserve channels, using special sealing products, special sleeves and protective pipes, heat-shrinkable parts, etc.

When used for sealing the inputs of heat-shrinkable parts into the foundation of a service building, one or more metal pipes are embedded (depending on the number of pipelines supplied). The diameters of the pipes must be such that the incoming pipelines pass through them with a gap of 5-10 mm.

When introducing a pipeline into an existing service building, a hole is first punched, after which a sleeve is fixed in it with a cement mortar. To ensure the round shape of the sleeve, it is advisable to insert the pipe into it before the hole is cemented.

Pipelines introduced into the building must be attached to the wall or on a special frame in the immediate vicinity of the input so that the ends of the pipelines are at a height of 1.2-1.5 m from the floor of the room.

The placement of cable stocks in chambers or wells is allowed in exceptional cases if it is impossible to place these stocks inside the building.

An approximate plan and scheme for installing a fiber optic cable inside a building is given in "Appendix B".

Main menu

Cable entry into buildings

When it is necessary to protect cables from mechanical damage, from the effects of aggressive soils and stray currents, they must be laid in pipes. For this purpose, steel, cast iron, asbestos-cement, ceramic and plastic pipes are used.
The pipe material is determined in the project. It is allowed to replace one type of pipe with another, but this must be specified in the project.
The inner diameter of pipes for laying cables with single-wire aluminum conductors with the symbol "Ozh", for example AABL (OZH), as well as for cables of the AAShv brand, must be at least twice the outer diameter of the cable. For other brands of cable, the diameter of the pipes is at least one and a half times the diameter of the cable.
Pipes must meet the following requirements:
their inner surface should be smooth;
pipe ends with inside must be rounded with a radius of at least 5 m and not have protrusions, kinks, burrs;
pipe connections must be strictly aligned;
the ends of the pipes at the points of entry (exit) into the tunnels, the channels must be sealed flush with the inner surfaces of the walls.
Pipes must be laid with a slope of at least 0.2%. Pipe connections should be made using metal, plastic or rubber cuffs or asbestos-cement couplings.
When forming pipes into blocks, the clear distance between the pipes vertically and horizontally must be at least 100 mm. In this regard, the lower pipes of the block must be laid to a great depth so that the upper pipes of the block are from the planning mark at a depth of 0.7 m.
Cables with plastic protective covers of the AAShv type are laid in pipes only in straight sections with a length of more than 40 m and at the entrances to buildings and cable structures. When laying cables of the AAShv type in the ground, for each cable section, regardless of its length, no more than four transitions in pipes with a total length of up to 20 m or more than two transitions in pipes with a length of more than 40 m are allowed.
The ends of the pipes after laying cables in them are sealed by winding several layers of resin tape or cable yarn (jute) onto the cable, followed by its padding. Cable entries into buildings and structures are sealed according to the instructions given in the project. Pipe sealing for trenching during cable entry and cable construction:

Cable entry through a pipe into buildings or cable structures:
a) - in the absence of soil subsidence, b) - while waiting for soil subsidence, 1 - cable, 2 - pipe, 3 - seal, 4 - waterproofing, 5 - sand without impurities clay and stones, 6 - the wall of the building.