Heat shrink tubing is used for sealing, marking and insulating cables, wires and other similar components. Shrink insulation is distinguished by its compactness, aesthetic and professional appearance. In the seated state, the tube retains its shape, fits snugly to wires, terminal blocks and connectors. When overheated, the heat shrink does not collapse, retains its properties and becomes soft.

Depending on the application, thermotubes have different characteristics:

• shrinkage factor;
• wall thickness;
• adhesive compound.

Colored and thin-walled shrink tubes

Colored, transparent and black heat pipes with a wall thickness of less than 1 mm after shrinkage are used for marking and insulating wires. Their shrinkage ratio is in the range from 2 to 1 to 4 to 1.

Special properties of tubes:

• heat resistance;
• self-extinguishing;
• resistance to ultraviolet radiation;
• low shrink temperature;
• zero emission of halogens during combustion;
• resistance to mechanical and chemical influences.

Thin-walled tubes do not contain an adhesive layer.

Medium-walled and thick-walled thermotubes

Characteristics:

• wall thickness - 1.5-4.5 mm;
• shrinkage ratio - from 2 to 1 to 6 to 1;
• hot glue is applied to the inner surface.

For insulation power cables with an average voltage level, thermotubes with specified chemical and dielectric properties, for example, track resistance, are used. Pipes are mounted using sealing and insulating mastics.

The principle of working with thermotubes is quite simple, but there are certain nuances that a novice electrician needs to know:

1. The size of shrink tubes is indicated by a fraction, where the numerator contains the initial diameter, and the denominator, respectively, the diameter after shrinkage. Additionally, the color and length of the segment is indicated.

2. The initial diameter of the thermotube must be greater than the diameter of the product on which it will be put on. For a snug fit, after heat shrinking, its dimensions should be at least a little smaller sizes products.

3. The stronger the shrinkage, the thicker the tube walls will be.

4. Longitudinal shrinkage in length is 5-10 percent.

5. There should be no burr on the ends of the tubes, and on the surface - deep scratches and other damage.

There are several ways to heat up when working with HERE heat shrink tubing. Each of them can be used with different types heat shrink, but some may not fit or even ruin the insulation.

The cheapest and most controversial option is matches. They are used when there is no other tool at hand, and heat shrinkage of very small sizes and sections. For large sizes it's not the best option.

The result is not a very neat form of compression of the tube, and the whole process can take a long time when it comes to larger products. And how many matches will be required if you need to isolate not one connection, but several dozen?

A lighter in this matter is also not always an assistant.

In those rooms where it is impossible to use a flame or an open fire, they try to adapt an ordinary hair dryer for drying hair. However, he is not able to create the required temperature for high-quality shrinkage compression.

The optimum shrinkage temperature is from 90 to 140 degrees, depending on the brand of the product.

A household hair dryer has a low outlet temperature, just a few centimeters from the nozzle, it can give out about 70C. Highly focused nozzles can help with heating small diameters, but the use of non-standard ones leads to the failure of the hair dryer itself. But there are thermotubes with a shrinkage of 350 degrees!

As a result, you may end up with an uncompressed or not completely isolated junction, where water can easily penetrate and absorb moisture. Therefore, instead of using improvised means, try to always use a professional tool.

Pipe tool HERE

In fact, there are 5 types of such a tool for heat shrinking in everyday life:

• • high-temperature building hair dryer (choice + order)
  • portable butane gas-burners(you can buy)
  • gas soldering irons (check current prices)
    
  • propane burners
    
  • infrared burners

    The industrial hair dryer is the ideal tool for thin wall tubes. It has in its assortment not only temperature control, but a variety of nozzles. You can choose the required set for yourself by following the link.
    

    Of course, if you are not the owner of a cordless tool, then you can only work with a building hair dryer if you have 220 volts nearby. Even the presence of a generator does not always guarantee the normal operation of the hair dryer due to its high power.
    

    Characteristics

    

    This is its main drawback and inconvenience. In addition, it is not always possible to warm up thick-walled tubes even with a powerful hair dryer. The quality here will obviously suffer.

    Even before you start working with a hair dryer, you will have to hold the tube a little. Otherwise, a powerful jet of air can move it from its place. Infrared burner in this case has an advantage. It does not create air currents, and its rays warm up very quickly.
    

    Just be sure to keep in mind that dark pipes absorb heat much faster than light or multi-colored ones. Forgetting this, you can easily burn through the insulation.

    Gas burners have several flame functions. Heat pipes should be shrinked with a soft flame. How to understand that the flame is soft and suitable for shrinkage? It must contain languages yellow color. The same applies to gas soldering irons.
    

    A propane torch is the only tool that is optimally suited for thick-walled pipes.

    When working with a burner or a hair dryer, you need to constantly make circular translational movements. Do not stop in one place, otherwise you can easily burn through the insulation.

    In general, the choice of shrink tool depends on the following options:

    • wall thickness
    • tube size
    • the material from which they are made

    You can read more about these characteristics in the article “10 types of heat shrink tubing.”
    

    Rules for installing heat shrink tubing

    
    

    There is no need to rush though. First, the product warms up and shrinks around the entire circumference, and only then can you move forward gradually.

    • remember that heat shrinkage decreases not only in diameter, but also along the entire length

    The decrease, of course, does not occur by 2.3 times, but by several percent (maximum 15%). So do not be surprised if the tube HERE was originally 10 cm, and later became shorter by 1.5 cm. Therefore, when choosing the right size segments, always make a small margin.
    

    The reduction in length is especially noticeable when connecting and insulating materials of different diameters.

    For some reason, everyone forgets to take into account the height difference in this case, and it also takes a decent margin.
    

    If you do not know for sure whether the selected size will be sufficient or not, then in this case it is better to ignore the above advice about starting warming up from the middle.

    Here, follow a different rule - heat the tube not from the middle, but from one end to the other. Thus, it is possible to reduce the longitudinal contraction of its length.

    • when the heat shrink isolates any metal surface or a product with good thermal conductivity, it is necessary to preheat this surface.

    In this way, the walls stick together more tightly and the so-called “cold scars” can be avoided. First of all, this applies to tubes of large diameters; without preheating, it is unlikely that it will be possible to avoid skew.
    

    In addition, due to temperature differences, condensation can form, which you "seal" directly onto the insulation. In general, any surface of the material must be cleaned and degreased before work. This is done with a cloth soaked in alcohol or solvent.
    

    If there are extraneous sharp edges on the metal, then they need to be removed and sanded.

    • when cutting and shortening the tube yourself, do it with a sharp knife, and preferably with scissors, so as not to leave burrs. Its edges after the cut should be smooth, only in this case the tube will be seated as tightly as possible.

    
    

    Of course, in this way it is possible to increase its length by more than two times.
    However, at the same time, the thickness of the insulating wall also decreases by the same two times. And, accordingly, the electrical strength will already be within smaller limits (for thin-walled ones, this is usually 600V), and someday the phase will definitely break through to the case or another core.

    In addition, the mechanical strength also decreases. How long your connection will now last is a mystery. If, of course, you use this option for low current, telephone cables or USB, then something may work. Plus, no one forbids in the same way to put on top of the first layer, another such stretched thermocambric.

    In the same way, some people manage to increase the width with round-nose pliers, expanding the tube while still cold.
    Thus, trying to make an analogue of expensive 4k1 from cheap HERE 2k1.

All electrical wiring must be safe for human life. This is one of the most basic requirements for electrical installation. It is especially necessary to remember the places where the wires are connected, because it is there that overheating, contact failure or even fire can occur. That is why in these places it is necessary to make reliable insulation. One way to insulate is to use heat shrink tubing (SHT). This type protection has many advantages over other types of protective insulation for cable connections. But in order to properly use heat shrink, you need to know what it is, what such a tube is for, and how to choose the size. It's about this will be discussed in this article.

Main purpose

The main purpose of heat shrink is to isolate current-carrying conductors. Due to the electrical insulating properties and easy installation, conventional insulating tapes can be successfully replaced.

AT given time You can easily buy heat shrink tubing in electrical stores, which are used for protection. Popularity this product as an insulating material lies in the ability to reduce its diameter due to high temperature. The required shrinkage temperature reaches 120°C. However, in order to do this, you need to know how to heat the heat-shrinkable tube. Due to the heating, the heat shrink wraps very tightly and reliably around the insulated object, providing good insulation, as well as providing mechanical protection for wires.

Manufacturers produce tubes different sizes and they are also color-coded. Due to this, they are used not only for good insulation, but also for further determining the purpose of the insulated wire.

For example, for marking wires direct current use red for plus and black for minus. And for marking five-core electrical cables brown, white, black are used, which indicate phase conductors, zero is indicated in blue, grounding is yellow-green.

The use of HERE for cable marking is quite convenient, because the heat shrink tube does not need to be pulled over the entire length of the wire. You just need to stretch a small piece of heat shrink over the insulation to the end of the wire, as shown in the photo above. This marking is very reliable, and is not afraid of external influences, as well as temperature changes. Its service life is more than twenty years. This product is durable, inexpensive and very easy to use.

Advantages and disadvantages

Compared to other types of insulation, heat shrink has at least four advantages.

Firstly, since the heat shrink tube fits very tightly, it does not move due to various mechanical influences. Secondly, installation is a simple and fast process, but you still need to know some rules of use. Thirdly, after shrinkage, the insulation material becomes more durable, so the wire becomes even more resistant to mechanical damage and acquires additional rigidity at the junction. And the service life is much longer than that of conventional electrical tape. The fourth plus is a wide scope.

Among the shortcomings of the HERE tube, the following can be noted:

1. It is impossible to reuse, because when heated, it changes its diameter, so it will definitely be damaged when removed.
2. The price of a heat-shrinkable tube is higher than the price of electrical tape, but not so much that it becomes a decisive factor when choosing a protective and insulating material.

If any other shortcomings are found during use, then these are the shortcomings of the selected manufacturer.

The video below provides a visual comparison of heat shrink and electrical tape:

Where is the tube used HERE

While heat shrink tubing's primary purpose is to insulate contacts, there are other ways to use it:

• Insulation of plumbing and metal pipes from aggressive environment.
• Shrinkage on a metal butt or wooden support Power lines in order to protect against corrosion and decay of wood in the ground.
• Longitudinal sealing of cable bundles. Despite the external insulation, you can use a special tape that completely fills and also insulates the space between the conductors of the wire.
• To improve the ergonomics of sports equipment handles and construction tool thanks to the use of corrugated and ribbed tube surfaces.
• Converting simple tools like screwdrivers to insulating ones with insulation HERE.
• Wire protection against high temperature. There are products, the operating temperature range of which varies from -65°С to +260°С. This protection helps the wire to withstand such working conditions, even if there is a source of heat and fire nearby. Such types of heat-shrinkable tubing are called fluoroplastic or teflon.

Characteristics of a heat -shrink tube

First you need to know what a heat shrink for wires is made from. They make it from the polymer, thanks to this it can change and contract. The size of the tube here can be reduced twice and even all the same. The coefficient of shrinkage of the product varies in the range from 2: 1 to 6: 1.

Also, heat shrinks come with an adhesive layer, they are used when the joints need to be very securely sealed to protect against moisture and corrosion. The adhesive layer achieves additional strength of the compounds.

Thermal tubes are different with the composition of the polymer. Some are made from PVC, elastomers, polyolefins, and various other materials. It is important that the product is resistant to fire, UV rays, and also that it has good mechanical properties.

It is also important to talk about the dimensions of heat-shrinkable tubes. All manufacturers put a designation on the product that will indicate its dimensions. The diameter is given both before and after shrinkage. The first digits indicate inner size before shrinkage, and the following are either the diameter or the coefficient by which it can be calculated. The basic or standard ratio is 2:1. The maximum tube diameter of HERE is 120mm and the minimum size is 2mm before shrinkage.

Most the right dimensions heat shrinks are provided in the table:

If you want to know how to choose heat shrink tubing, please watch the video below:

How to use heat shrink for wires

It remains to learn how to use heat-shrinkable tubing. So, first you need to choose the appropriate size of heat shrink. If necessary, it is necessary to cut off a suitable piece that would overlap the insulated area, taking into account the fact that there will be longitudinal shrinkage when heated. Usually it is up to 10%, this information is indicated by the manufacturer. On the surface, as well as on the sections of the cut tube, there should be no damage or any burrs, because they can contribute to the rapid destruction of the material.

First, a tube is pulled over the cable HERE, and then it is necessary to make a connection, over which heat shrink will be put on. After joining, it must be heated with movements from one side to the other, in order not to get a large longitudinal shrinkage. It can also be carried out by heating from the middle of the connection to the edges. The second method is applicable in fairly long areas.

It should be remembered that it is impossible to warm up at the same time from both ends because an air bubble may remain, and this is very undesirable. Wrinkles may also appear on the surface. The heat-shrinkable tube should be heated very carefully and evenly so as not to overheat in some place, because a bubble or a break in the surface may appear.

The heating rate and temperature is determined by experience. However, one should not rush, especially if there is no experience in this direction. Heating up too quickly or at too high a temperature may damage the heat shrink.

The insulation process itself is not too complicated; if desired, you can independently insulate the wire. However, to begin with, you can experiment on some piece of wire and make sure that everything is done correctly, and only then take on the isolation of critical connections.

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In the process of performing work related to electricity, it becomes necessary to use a heat-shrinkable tube. We will talk about the features, varieties and scope of the heat-shrinkable tube further.

Features of the manufacture of a heat -shrinkable tube

For the manufacture of heat-shrinkable tubing, materials based on heat polymer are used, which have heat-resistant characteristics. In the process of increasing the temperature, thermal polymers change the shape and expand.

For the manufacture of heat shrink tubing, polyethylene is used, obtained by using low or high pressure.

By means of chemical and radiation exposure, hydrogen atoms are released and the process of fusion of molecules occurs. It turns out a fairly durable material that has high heat-resistant characteristics. After that, the material is heated, which acquires additional elasticity, but does not melt. Under the influence of high temperature, the heat polymer is able to stretch, change shape and shrink, depending on the required size.

After heating, the material has a shaped memory, which is easily restored during reheating.

For the manufacture of heat-shrinkable tubing, use:

• polyethylene,
• polymers of polyolefin composition,
• polyvinylidene,
• polyethylene terephthalate,
• polyester,
• PVC,
• fluoroelastomer.

Main properties and requirements for heat shrinkable tubes:

• resistance to high temperatures,
• resistance to acid and alkaline solutions,
• elasticity,
• ease of deformation
• lack of flammability
• ease of extension of the tube in the presence of a gap of 300%,
• the value of strength in the process of stretching is not less than 15 MPa,
• operating voltage up to 100 W.

Most heat-resistant tubes are capable of operating in temperatures ranging from 55 to 120 °C. Some products are able to withstand temperatures up to +270 °C.

The principle of operation and the scope of use of heat shrinkable tubing

Heat shrink tubing is used as a complete insulator for the protected item. The properties of the heat shrink tubing allow it to shrink and change shape during heating. Thus, the tube, which is located on the object, under the influence of high temperature, completely repeats the shape of this object and provides insulation.

The scope of use of heat-shrinkable tubing is more expanded than that of electrical tape, which performs almost the same functions.

Thermal insulation tube is most often used to electrically insulate wires, terminals or contacts.

Areas of use of heat shrink tubing:

• cable production,
• electricity, as an electrical insulator,
• sealing of electrical equipment,
• repair, installation of cable couplings of connecting type,
• insulation and marking of electrical wiring,
• to recognize the wires use a heat-shrinkable tube of various colors,
• as an insulating material in the manufacturing process of electrical equipment,
• telecommunications and energy saving industry during installation and cable laying,
• as additional elements in nuclear power,
• mechanisms that work in the aviation, shipbuilding, automotive and railway industries, protects against high temperatures, acids, alkalis and water.

Also, heat shrink tubing is used to repair damage to electrical wiring, protect electric wires from corrosion.

Benefits of using heat shrink tubing

• excellent protection of electrical appliances from mechanical and thermal influences,
• a variety of colors will help you choose a heat-shrinkable tube in relation to the color of the device,
• ease and simplicity of installation,
• the possibility of splicing several elements,
• providing high-quality plugs and filling irregularities,
• low cost,
• the absence of harmful components in the composition of the tubes.

Varieties of heat shrinkable tubes

Depending on the principle of operation and the device, heat-shrinkable tubes emit:

1. Adhesive heat shrink tubing, which are highly popular. Such tubes are equipped with an internal adhesive layer, which during heating helps to seal the joints. Thanks to this, the tube is attached to the object more firmly and provides a high level of protection against moisture. The value of the shrinkage coefficient of such tubes exceeds 300%. A heat-shrinkable tube with an adhesive layer is used to isolate objects in which the size differs significantly from the diameter of the tube.

2. Heat-shrinkable thick-walled tube - made of polyolefins. They are more widely used than adhesive because of their affordable cost and ease of use. These tubes come in a variety of colors. Thick-walled heat-shrinkable tubes are divided into:

• tubes with flame suppression,
• tubes with no flame suppression.

The first option contributes to self-attenuation, in the absence of open fire thanks to the use of non -combustible substances, during the manufacture of tubes. Such tubes are used as an insulator in explosive industries, in the production of electrical equipment or in some military developments.

3. Special heat-shrinkable tubes - used to perform additional insulating functions in specialized enterprises.

Among the special heat -shrinkable tubes are highlighted:

• fluorescent type tubes - used in rooms with low light, after receiving light during the daytime, such tubes emit light at night;
• tubes with high voltage characteristics are used for high voltage electrical networks;
• Teflon-type tubes have an aggressive or high-temperature environment of use;
• corrugated tubes - used to cover the handles of tools or electrical appliances.

Installing heat shrink tubing professionally requires the use of a special tool, such as an industrial blow dryer or heat gun. Such a tool must have the property of temperature control and various nozzles. Alternatively, at home, use an ordinary lighter, gas burner, matches, a regular hair dryer, or boiled water.

Before installing the tube, the surface of the object must be degreased and, if necessary, cleaned. To select the type of tube that is suitable for insulation, the following criteria should be considered:

• ease of installation
• ease of use,
• Terms of Use,
• material requirements.

Considering specifications Pipe pay attention to such parameters as:

• The diameter of the tube after shrinkage,
• temperature regime work,
• moisture resistance,
• working stretch,
• strength in the process of stretching.

When choosing a thick-walled tube, before installation, the tube should be heated, then put on the object, and then heated to the required shrinkage temperature.

When cutting the tube, be careful not to have any nicks or rough cuts on the end of the tube.

During shrinking of the tubing, the recommended temperature specified by the manufacturer should not be exceeded. This will cause the tube to twist or wave-like structures.

Shrink the tubing from the middle to the ends, especially when installing the adhesive heat shrink tubing.

Criteria for the correct shrinkage:

• The absence of Zazubrin and waves,
• smooth surface,
• no bulges.

Photo of heat shrink tube:

heat shrink tubing cost

You can buy a heat-shrinkable tube in a specialized electrical store or on the market. The heat-shrinkable tube price depends on the quantity and quality of the material from which the tube is made. The higher the temperature regime of the tube, the higher the cost. The average price for 1 m of heat-shrinkable tubing is $5.

Overview of Heat Shrinkable Tubing Manufacturers

1. TE CONNECTIVITY is a company that manufactures heat shrink tubing. Consider two tube production series:

ATUM - heat shrink tubing with an adhesive backing, which differ high level shrinkage and have an average wall thickness. It is used as a sealant for such materials as:

• plastic,
• rubber products,
• steel,
• copper.

Versafit are flexible heat shrink tubes that are characterized by a high level of fire resistance and a low shrinkage temperature. This series is a tube that provides excellent strain relief and resistance to mechanical stress.

2. Rauchman CFM - Adhesive based heat shrink tubing. It is used to seal objects and protect equipment from corrosion. The company produces two types of tubes: with suppression and without combustion suppression.

Peculiarities:

• black color,
• operating temperature from -55 to +90 degrees,
• production material - polyolefin,
• function - protection of equipment from mechanical damage and moisture.

3. ZM BBI - Russian company for the production of heat shrinkable tubes.

Peculiarities:

• resistance to high temperatures,
• good elasticity,
• a variety of colors and sizes of tubes,
• the presence of a tight fit to the subject.
• ease of shrinkage
• resistance to chemical and mechanical influences.

Scope of use:

• protection of tires of round, rectangular and square shape,
• bolt protection,
• armored switchgear protection,
• use for isolation of electrical substations.

4. HERE - a heat-shrinkable tube that provides reliable protection from moisture, corrosion and mechanical stress.

Peculiarities:

• resistance to mechanical influences of the external environment,
• stability before ultraviolet radiation,
• antitoxicity,
• lack of maintenance of combustion,
• simplicity and ease of installation,
• a shrinkage temperature from 90 to 125 ° C,
• A variety of colors and the possibility of individual color selection.

Купить термоусадочную трубку во Владивостоке несложно, но её качество оставляет желать лучшего. Translucency bothers me the most. Ход мыслей прост: если термоусадка полупрозрачная, как обложка для школьной тетради, то и изоляция у неё плохая. А если честно, то все эти полурозовенькие и недозелёненькие трубочки никак не гармонируют с моими проводами цвета исключительно красного, чёрного, жёлтого или белого.

Я предпочитаю покупать термоусадочные трубки в интернет-магазине hobbyking – там и цена более привлекательна, и качество трубок на порядок выше. Только не сочтите меня заядлым покупателем термоусадки: я закупился один раз и взял по метру каждой трубки из нужных мне диаметров и цветов – пока хватает, хотя запасы некоторых уже на исходе. If you need more, I'll buy it there. Как показывает практика, однометрового набора хватает на год неспешного пользования. Термоусадочные трубки маркируются по изначальному, первичному диаметру, то есть по размеру до усадки. On average, all heat shrinks shrink twice evenly. Some more, some a little less. В любом случае, стоит подбирать трубку так, чтобы диаметр провода был чуть больше, чем половина диаметра термоусадки. Например, термоусадочная трубка 14 мм уменьшится до 7 мм – в таком случае её нужно использовать с проводом не менее 8 мм в диаметре.

How to heat and shrink heat shrink tubing?

Most the right tool for such work there will be a soldering dryer. However, this thing is not cheap and buying it just for the sake of heat shrink is stupid. Если у вас есть паяльник с регулировкой температуры или паяльная станция, то можно прижигать трубку толстой частью паяльника. Not a sting, but the place where he hides heating element. Quite a working option.

Can an open flame be used for heat shrinking?

By an open flame, I mean any source of fire: a match, a lighter, a candle. В принципе, открытым пламенем трубку можно усаживать, но надо помнить несколько моментов:

1. The tube with a sharp shrinkage can be deformed and slip
2. With due diligence, heat shrink tubing can be burned through
3. The colored tube may become sooty

The main problem with using an open flame is that the source is always at the bottom, so the structure must be constantly rotated over the flame so that the tube is compressed evenly. By the way, it is advisable to keep it three to four centimeters from a visible flame: the temperature is most optimal there. It is not necessary to stick the tube directly into the flame or its base: the temperature is lower there. I do not recommend using turbo lighters and gas burners - the pipe will deteriorate in an instant!

Why is heat shrink better than classic blue electrical tape?

First, the tube does not unwind over time. Secondly, it does not stick to the insulated material and does not leave an adhesive layer on it. And when correct selection color and diameter looks more aesthetically pleasing. By the way, it is much easier to remove the tube: it is enough to make a longitudinal incision. Heat shrinkage is also indispensable for isolating closely spaced contacts, for example, on connectors: it is not necessary to wrap it, therefore free space not required.

Why is heat shrink tubing worse than regular blue electrical tape?

Is it that it cannot be used to isolate structures complex shapes, whose size changes. If the connector has a diameter of 10 mm, and the wire is only 3 mm, then the tube simply will not reach the wire or fit on the plug.

What sizes are there?

The hobbyking site has tubes from 2 to 100 millimeters. I once was in a store with electrical goods and all sorts of powerful things - there were heat shrink tubing with a diameter of 25, and, if I'm not mistaken, even 50 centimeters. Tubes up to one or two centimeters in diameter really look like tubes. And the larger ones are flattened into stripes and look like a ribbon. It is important to remember that they are all marked precisely by the diameter, and not by the width of the flattened tape. For example, a red tube with a diameter of 14 mm looks like a tape with a width of 24 mm.

The diameter of the tube and its width in a flattened state are two different things!

Which ones to take?

I'll tell you on personal experience. So here's what I bought:

• 25 mm, transparent - convenient for isolating ESC and any USB boards (hubs, modems, wi-fi whistles)
• 16 mm, transparent - suitable for connectors and some small boards, sensors or sensors
• 14 mm, red - I practically didn’t use it, because I took it for my ESCs, but didn’t calculate the dimensions; most often I cut it into thin rings and mark some cables; it is also indispensable for my Turnigy 4WD Rally car
• 6 mm, blue - for power wires; because of the color that is not the most popular for me, it was practically not used, but it will be useful for many electricians
• 6 mm, yellow - for power wires; used more often since I use the 12 volt line extensively
• 6 mm, black - actively used for wires and connectors (3.5 and 4 mm bullet)
• 5 mm, black - the absolute leader in use in its diameter, ended
• 5mm yellow - used to insulate motor connectors (3.5mm bullet)
• 5 mm, blue - helps in the color differentiation of wires, although it is not so actively used
• 5 mm, red - the second place in terms of use in its diameter, I already have very little of it left
• 4 mm, black - completely over, you need to re-order
• 4 mm, red - a little bit left and still comes in handy
• 4 mm, yellow - there is quite a lot left, usually 12 volts are not carried out with such thin wires
• 3 mm, black - over, because it is very useful for almost all wires
• 2 mm, red - ended quickly
• 2 mm, black - ended even faster

Obviously, the most popular with me are small diameters, but this is understandable: small models are thin wires. Diameters of 5-10 mm will be of interest to electricians and car enthusiasts: the former work with serious wires, while the latter like to seal everything. Larger diameters have even more specific applications, except for one: heat shrink can be stretched over the handles of the tool and make it more convenient (and electrically safe) to handle. I use large gauges to insulate modules and boards.