Which cable to choose for installation outdoors (over the air and in the ground)

Armored cable design

Cable products with a layer of armor in their design are not much different from similar products that do not have a protective sheath. These conductors of electrical energy have the following components.

1. Conductors are metal conductors of electricity. The number of these elements can be from one or more. According to their shape, the cores can be round, flat, segmental, rectangular or sectoral. They come in either a monolithic design or consisting of many thin wires connected into one structure. The cores are made of copper and aluminum, in rare cases of steel, and for specialized cable products from gold, silver and superconducting alloys.
2. Insulation of current-carrying cores - this layer isolates each current-carrying core from each other, as well as from the influence of the external environment. For its manufacture, polyvinyl chloride polymer (PVC), special rubber, polyethylene, impregnated paper and other synthetic materials can be used. In most brands of armored cables, the core insulation is multi-colored. This is necessary to simplify installation work and quickly determine the purpose of each individual core by color. The entire set of current-carrying conductors is protected by belt insulation.
3. Internal fillers - seal the internal space between different parts of the cable. Provide additional mechanical strength and rigidity of the entire product structure. Both synthetic and natural products are used as materials for the manufacture of fillers: special cable yarn, impregnated paper, polymers, rubber and even oil. The filler must have high dielectric characteristics and sealing properties.
4. The shielding layer is an optional element of armored cables. Installed in those brands of products that are designed to operate in conditions of strong external electromagnetic radiation in order to reduce its effect on current-carrying conductors. In addition, screens make it possible to reduce the intensity of the electric field of the armored cable itself, which in some cases is a necessary condition for its operation. Screens are made from metals in a protective shell, conductive paper and other materials.
5. The cable sheath with cushion is the outer layer of the product, protecting the entire internal part from moisture and mechanical stress. Various materials are used for its manufacture: PVC, rubber and other polymeric substances, and in special cases the outer layer is covered with a lead sheath. The cushion is necessary to protect the protective outer shell from damage by the metal armor layer. It is made from bitumen or special cable yarn.
6. Steel armor is a layer that protects current-carrying conductors from possible mechanical damage during installation and operation. It can be made either from two galvanized steel strips or from intertwined steel wires coated with zinc. Tape armor is more reliable than wire armor, but a product with such protection is more expensive. Depending on the operating conditions, a cable with the armor that is optimally suited for the application is selected.

The advantages of armored cable products include high moisture resistance and strength, durability, excellent anti-corrosion properties and a wide operating temperature range. The disadvantages of these products are low flexibility and high price.

Cable cushion

To prevent damage to the sheath, as well as to reduce the risk of the spread of wire corrosion from the armor, a special cushion is used, which is represented by a circular winding of cable yarn impregnated with bitumen. In addition, the protection is made of creped or bitumen-treated paper with a top bitumen layer.

— For the production of cable yarn, popular fiber is used, which is specified in GOST 905-78.

— To produce crepe paper in accordance with GOSTs 10396-84 and 9840-74, water-repellent paper is used, which is glued in two layers with a bituminous composition of the BND-40/60 or BN-70/30 grade.

— For cable paper, half-tar impregnation is used, the composition of which includes copper naphthenate (GOST 645-67).

The reinforced protective cushion is created from fiber in combination with plastic strips, the width of which ranges from 25 to 90 mm. The tapes are applied overlapping, which significantly increases the resistance of the wire’s structural elements to corrosion. To indicate a reinforced protective cushion, the cable marking includes the letter “l”. The double layer of tapes is marked accordingly “2l” (AB2l).

Power Cable Types

The following types of power cables can be distinguished:

• VVG
• NYM
• VBBSHv

VVG cable

Capable of transmitting current up to 1kV, with copper conductors and PVC sheaths. The outer shell is also made of black, sometimes white, polyvinyl chloride. Inside there are wires of different colors, so that, according to generally accepted standards, the zero is not confused with the phase and the “ground”. General standards will help when repairing wiring.

Features of VVK:

• number of cores 1-5;
• monolithic or multi-wire, the latter more flexible and durable;
• the cross-section of the cores is from one and a half to two hundred and forty millimeters square.

In household use, conductors with a cross-section from one and a half to six millimeters square are used. To supply electricity to the private sector, cable products with a cross-sectional area of ​​sixteen millimeters square are used.

When choosing the required electrical cable, it is necessary to calculate the cross-section of the wire depending on the power. This can be done using an electrical manual. Add a margin of 20-25% to the found value.

A correctly calculated cross-section of an electrical cable or wire is the key to the safety of your home.

NYM

NYM is an imported analogue of VVK. Its core is always copper and stranded. An ideal option for wiring in apartments.

VBBSHv

External insulation made of steel, lead or aluminum. This makes it possible to lay it underground, in the air, in sewer holes and pipes.

Rules for laying electrical armored cables in the ground

• laid in a trench with a depth of 70 centimeters in open areas and from a meter in residential buildings; • the cable is checked for integrity; • the distance between other cables is at least 10 cm. It must be remembered that the higher the cable power, the greater the distance should be; • the cable is positioned straight and should not be twisted; • laying is carried out without tension; • the armor should be grounded; • sand should be poured onto the cable in a layer of 10 cm, then a layer of ordinary red brick and signal tape should be placed. And only after that they fill the trench with earth; • all layers of soil are compacted.

Some nuances need to be taken into account:

• if there is a heating main nearby, there must be a distance of at least two meters to it; • the distance from water supply networks must be at least a meter; • if it is necessary to lay through highways or railway tracks, you need to use pipes and ducts; • if it is necessary to cross the location of other cables, they are insulated with a layer of soil at least half a meter thick.

There are three ways to lay cables in the ground:

• manual. The trench is dug with a shovel, the cable is laid and introduced into the room. The method is applicable on house or summer cottage plots; • mechanized. Suitable for industrial installation. A trench is dug with a bulldozer, then the cable is laid in the manner described above; • trenchless. Used for industrial purposes. A cable manager is used. This method can only be used to lay a single cable with aluminum filling and galvanization. Laying is done in open areas. If there are metal bridges or overpasses on the territory, then the cable is placed in non-flammable asbestos pipes. For wooden buildings, installation is carried out in steel pipes to avoid fire.

The armored power cable is manufactured in Russia according to GOST.

Types of closed drainage systems: advantages and features of use

Laying of armored optical cable is carried out in the following types of soil:

• permafrost; • the bottom of any reservoirs; • sand, loam, gravel and ordinary soil.

Which armored cable to use for laying in the ground depends on the type of work: laying communication lines or electrical networks. In addition, when choosing the type of cable, you must be guided by the PUE (electrical installation rules). Laying an armored cable in the ground according to the PUE will indicate all the nuances of professional installation.

Where laying armored cables is prohibited is indicated in the construction standards. It cannot be laid under the foundation of a building. The distance to the building must be at least 60 centimeters. It is strictly prohibited to cover the cable with earth containing metal waste. In addition, laying cannot be carried out mechanically at a distance of less than a meter from highways and railway tracks, as well as reservoirs. There is also a ban on laying cables in explosive zones without a protective pipe.

As stated above, it is prohibited to lay cables without fire-resistant protection on metal and wooden bridges.

You can buy armored cables for laying in the ground directly from the manufacturer, on dealer websites or in specialized stores. The price depends on the section. The cost of an armored cable with copper fibers starts from 90 rubles per meter, the cost of aluminum - from 98 rubles, optical - from 60 rubles.

The laying of armored cables indoors is carried out for conditions with an increased risk of fire or flooding. Aluminum or optical cable is used. It can also be mounted at a significant height or under water. This cable is installed in special pipes or boxes. Wall mounting possible.

The armored cable is universal, it can be used for any weather conditions and soils. It will withstand temperature changes and last about 50 years. You need to choose an armored cable based on the intended purpose, type of load, PUE and SNiP.

How to lay it in the ground

We reviewed above the brands of cables for laying in the ground; many of them are also suitable for laying along the bottom of reservoirs. Let's look at the features and dangers of laying cables underground:

1. Tree roots often do not pose a particular danger, but still affect the line in a negative way.
2. Movement of soil, especially stones and pieces of construction waste contained in the soil.
3. Possibility of damage during “excavation” of communications by other services or when digging foundations for future buildings.

Armor protects to some extent from these factors; sometimes the cable is additionally laid in a protective pipe, for example HDPE or corrugated.

The cable in the ground should be laid without tension, freely, possibly with slight bends. A sand cushion is poured into the trench before laying the line; it will provide additional protection. The cable is covered with soil, after a short distance (20-30 cm above) a bright-colored warning tape is laid; now bright tapes are also being produced with inscriptions like “CAUTION CABLE!”

Before and after burying, check the line for short circuits, since during construction work damage to the insulating parts is possible.

BKZ gasket

The armored cable is laid in the following sequence:

1. A ten-centimeter layer of sand is poured onto the pre-leveled bottom of the trench. The sand should not contain pieces of glass, stones or other objects that could subsequently cause damage to the cable insulation due to external force impacts on the sheath.
2. The sand cushion is slightly compacted (even compacting the sand with your feet is allowed) so that there are no obvious irregularities: humps and holes.
3. After visually checking the integrity of the BKZ for absence of damage to the insulation, the cable is laid on a sand bed. The cable thread should be laid in free twists, without tension, so as not to provoke the occurrence of tensile forces when the soil moves during operation.

Scheme of laying BKZ on a sand cushion

1. The cable line is checked for short circuits:

• between TJ;
• between the TJ and the armor.

The laid wire is covered with a layer of sand about 10 cm thick, which is lightly compacted with feet. A layer of previously excavated soil 15-20 cm thick is poured on top of the sand layer, which is also compacted. Lay a warning polymer tape with the inscription “Caution cable”, warning about the presence of a cable route when subsequently carrying out any excavation work.

Signal tape

1. The trench is filled to the top with soil to form a low bed. If the contractor buried the cable route without complying with this condition, then within a year the land above it will subside below ground level, which will lead to a deterioration in operating conditions.
2. A control check is carried out for a short circuit between the TJ and the ground.

Laying in the ground

The brands of armored cable presented above are suitable for placement in the soil; most of them are also applicable when installed along the bottom of reservoirs. Underground installation of products has its own dangers and nuances:

• Tree roots can negatively affect the drawn line. But usually their impact is not so significant.
• The risk of damage lies in the movement of the soil (especially the stones and construction debris contained in it).
• Disruption of wiring is possible when workers of other services dig up ready-made communications for construction or repair purposes. The cable may also be damaged during the construction of foundations for new buildings.

Armor can provide sufficient protection against such impacts. An additional reinforcement will be the laying of wires in corrugated or HDPE pipes.

It is also necessary to eliminate cable tension in the soil, with minor bends allowed. For greater protection, a sand cushion is placed at the bottom of the trench on which the wire will be laid. A bright signal tape is laid along the cable covered with earth at a distance of 20-30 cm (today you can find products with a warning label on sale).

The wiring is checked for the presence of short circuits before and after burying in the soil, since insulating layers may be affected during construction.

Marking of cables with a layer of armor

Armored cables are available in various designs, which are indicated in the product labeling. The marking standard is the same for all types of cables and wires. The marking code consists of a set of letters and numbers, where each letter symbol indicates a specific design feature or technical characteristic of the product. The absence of a letter can also indicate certain properties of the product. So, below we will look at the letter and number markings of armored cables.

1. Metal of current-carrying conductors: if it is “A”, then this is an armored aluminum cable, and if there is no letter, then this is an armored copper cable.
2. Type of outer shell: “B” - made of PVC (polyvinyl chloride); “P” - polyethylene; “Shv” - in a PVC hose; “Shp” - polyethylene hose; "C" - lead sheath.
3. Presence of a screen: the letter “E” in the marking indicates that this cable has a shielding layer, and its absence indicates the opposite.
4. Insulation of current-carrying conductors: “B” - made of polyvinyl chloride (PVC); “Pv” - stitched polyethylene; “P” is a polymer composite material.
5. The presence of a layer of armor: “B” - armor made of two steel strips, and an additional letter “b” for the absence of a bitumen cushion; “K” - armored with round wires.
6. Cable cut shape: indicated by the letter “P” if it is flat; marking is not provided for a round product.
7. According to the shape of the cores: monolithic ones are marked with the letter “o”, and stranded ones are marked with the letter “m”; segmental “s”, and round “k”.

In addition, the marking may contain other letters that determine the fire-fighting properties of the product. After the letter code there is a digital code, where the first digit indicates the number of cores, the second the cross-section of the current-carrying wires in mm² and the third the rated voltage.

Lightweight protective cover

Ensuring the resistance of cables and wires with rubber insulation to the influence of petroleum products and light radiation is ensured by yarn based on cotton fiber. For these purposes, undyed or colored twisted yarn is suitable, the thickness of which ranges from 10 × 2 to 18.5 × 2 tex (calculated based on the formula 1 tex = 1000/N, where N is the yarn number according to the standard metric), corresponding to GOST 10878 -70.

• Strengthening the strength of cable and wire products to mechanical stress is ensured by using windings made of flax thread or thick cotton yarn. To protect the flexible cord, matte and glossy sewing thread of dark colors or a combined two-color thread is used, corresponding to GOST 6390-70, which is folded in three and has a thickness of 21.7 × 3 or 13.2 × 3 tex. The optimal braid angle is from 25ᵒ to 70ᵒ. Reducing the slope will reduce the overall reliability of protection when bending the cable and will lead to exposure of the insulated wire. The thread density for different cables varies between 70-80%.
• For wire used in difficult operating conditions, the cotton thread must undergo additional processing, which increases the resistance of the braid to the influence of atmospheric conditions and rot. A mixture of bitumen, resins, paraffin and wax is used as impregnation. Such a protective cover allows the use of wires in conditions of constant influence of precipitation and solar radiation. The composition used to protect the braid from rot includes copper naphthenate, bitumen, petrolatum, ozokerite and other substances that prevent damage to the winding by fungus, mold, and insects.
• To protect cable and wire products with rubber insulation from the destructive effects of petroleum products - mineral oil, fuel and similar caustic substances - as well as from the influence of ozone, it is possible to treat the protective cover with varnish, for the manufacture of which cellulose ether is used. The composition of such a coating includes a mixture of organic solvents, as well as thinners with plasticizing additives.
• To increase the corrosion resistance of cables with polyvinyl chloride insulation used in aviation and during installation work, ethylcellulose varnishes are used in its production, which are a mixture of organic solvents with plasticizing additives and ethylcellulose.
• The resistance of their cotton windings to the influence of mold is ensured by impregnations with antiseptic additives - oxyphenyl and phenol compounds.

The heat-resistant cables, which are designed with silicone insulation, are braided with glass fiber yarn. Thread thickness is 6.7×2, 11.8×2 or 13.3×2 tex, in accordance with GOST 8325-70. According to the standard, the overall level of oiling of fiberglass should not exceed 1-2.5%. The use of organosilicon or glypthal varnish helps reduce the level of dust from fiberglass and improves its resistance to friction and increases strength. Conductor products with such protection can be operated at ambient temperatures up to +200 ᵒC, and when treated with F-4 suspension - up to +275 ᵒC.

Braiding the wire insulation with asbestos-impregnated thread makes it possible to ensure the fire resistance of the protective coating, reduce the risk of destruction of materials under the influence of acids and alkalis, and also reduce the thermal conductivity of the cable. This type of protection is used in the production of cable and wire products, which are in demand in metallurgy, where the operation of electrical networks near smelting furnaces increases the risk of cable melting. The product, which has a braid of yarn with the addition of asbestos, which is impregnated with bitumen and has a varnish coating with an organosilicon or graphite base, is suitable for installation as an output wire for an electric motor.

Application area

Single-core armored cables can be used to transmit electricity in DC circuits. As for the stranded version, it is most often used in the following cases:

1. If you need to conduct electrical wiring in the ground, tunnels, mines or trenches.
2. When installing wiring on a surface, but only if it is not subjected to significant tensile forces.
3. Outdoors, if there is a threat of mechanical damage, but subject to point 2.

At home, the cable is used if it is necessary to conduct electricity from the house to garden buildings underground. The only reason why it may not be used is the high price. In this case, it is recommended to use a cheaper armored analogue with aluminum conductors and similar characteristics - the AVBbShv cable.

Area of ​​use

Cables of this type are used when installing lines in mines, tunnels and trenches. They are laid directly into the ground without placing HDPE pipes or other protection options. But similar isolation measures can also be used additionally. The armored layer will protect the product from soil shifts and other harmful effects.

The protection prevents damage to the cable by various garden tools and tools, as well as rodents biting the wires.

If the voltage and mechanical impact on the network are minimal, then the product can be laid overland. The cable must be well fixed and protected from significant stretching.

A similar wire is used for domestic purposes to supply electricity to a home, summer kitchen, barn, garage, outbuilding and other similar buildings. In this case, an underground installation method is selected.

Underground cable route design

The owner receives a plan of the route from the pole to the building along with the project for connecting to the electrical networks, but he carries out the wiring along the site to the bathhouse, garage and other objects independently. The most economical option is to lay the cable in a straight line, but in reality this is rarely feasible, since you will have to work around various obstacles. When developing a plan for laying underground cables across a site, the following rules must be followed.

1. If possible, avoid intersection with other communications. If this can be done, then the cable without a protective sheath must be placed at a distance of no closer than 0.5 m from gas, water and sewer pipes. When laying the conductor in a casing, this distance is reduced to 0.25 m. When crossing with another electrical cable, this parameter is 15 cm.
2. It is necessary to bypass parking areas and vehicle entry areas. If this condition cannot be met, then it is necessary to increase the depth of the trench or pass the cable through a protective case. Large trees and bushes should be avoided. When passing the route along the foundation, the distance from it must be at least 60 cm.

As a result, the cable laying plan will correspond to a broken line, not a straight line. Marking the trench is best done with a stream of sand or pegs. After the preparatory work, it is necessary to once again check the plan for compliance with the standards and transfer it to paper, linking it to all objects on the site and underground utilities.

This drawing will subsequently be useful during the construction of new facilities, redevelopment of the site, as well as in the event of a need to repair an underground power line, which can happen if the technology for laying an electric cable in the ground is not followed or in other force majeure circumstances. The plan has been developed, transferred to paper - it’s time to start the main work!

Positive qualities of armored cable

The most obvious advantage of this product is its increased strength and ability to withstand heavy mechanical loads. In addition, the following “advantages” of cable protection with special armor can be noted:

1. The armored cable is resistant to corrosion and excessive humidity.
2. Long service life - from 30 to 50 years.
3. The product has no special requirements for storage conditions.
4. The cable is simply installed when laying the line.
5. Tolerates a wide range of temperatures from -50°C to +50°C. And the maximum permissible temperature for operation of the cores is 90°C.
6. The high reliability of the product minimizes all time and money costs for its use and repair in the event of cable damage.
7. The product is presented in a wide range, which makes it easy to find the required armored cable to complete an enterprise in any industry.

It would be unfair to remain silent about the shortcomings of this product. Armored power cables are not particularly flexible. However, the problem is not too acute when power lines are laid for many kilometers. If there is a need for a durable and flexible cable, manufacturers offer a product whose protective function is performed by a steel single-wire spiral. Using this type of armored cables, industrial and transport equipment is connected to electrical power.

Laying cables under the road

If it becomes necessary to lay a section of armored cable under a road, pond, or other structures, two options are possible:

1. Trench method. In this case, if the road is being laid under the road, the coating layer (asphalt, etc.) is removed. Its disadvantage is damage to the road surface, the final cost including restoration.
2. The trenchless method, also known as the HDD method or the puncture method. HDD stands for “Horizontal Directional Drilling”, the only disadvantage is the need to find equipment, this can be a problem in remote regions. This method is used for laying cables, water pipes and other communications.

In any case, laying a line under the road must be agreed upon with the organization responsible for the repair and operation of this section of the road, often with the city administration.

Types of armored power cables

The most famous types of power armored cable products are cables of the VBBbShv and AVBbShv types. The cross-sectional range of their cores is 1.5 – 240 square meters. mm. When the cross-sectional size exceeds 25 sq. mm, stranded cable cores, usually round or sector-shaped. The diameter of the armored cable type VBBShV and AVBBShV also varies: for example, 0.32; 0.5; 1.4; 13.4; 16.7 mm. The cable can be formed with a different number of cores (from 1 to 5), and in a 4-core product, one of the cores can have a zero value and be of a smaller cross-section than the other three.

The letter abbreviations used to mark the product mean:

• B – the conductors are insulated with PVC conductors;
• B – cable protection is represented by sheet armor, which is formed by two galvanized steel spirals. The gaps of the internal spiral in this design are overlapped by the external spiral.;
• b – bitumen layer. This feature is present in cables with a total core cross-section of more than 6 square meters. mm;
• Shv – the cable covers the outer PVC hose;
• A – the presence of conductors made of electrical aluminum in the cable. When this letter is not in the abbreviation, it means copper conductors.

Armored power cable type VBBbShv and AVBbShv is modified for voltage from 0.66 to 35 kV. Also, products of both types have standard color markings, which indicate phase and neutral conductors.

VBBbShv and AVBbShV cables are distinguished only by the material of the cores. Armored copper cable differs from its aluminum “counterpart” in its higher performance properties, but at the same time it has a higher mass per unit of conductivity and is more expensive financially. For this reason, armored aluminum cable has a wide range of applications today.

Features of armored copper cable

The armor of a copper power cable is able to protect the product from the most aggressive environments in conditions suitable for the installation of cable routes of a high level of strength. If this type of armored cable is not subjected to significant tensile loads, it can be laid outdoors with almost no restrictions. The product is fenced off from the external environment with several steel armored tapes packed in a special PVC hose. Thus, the power copper cable is securely hidden from rodents and mechanical damage.

Features of armored aluminum cable

This type of cable product does not have shielding. The cable is made from a current-conducting aluminum core with a round cross-section. Multi-wire conductors are used for large cross-sections. The insulating material in this case is polyvinyl chloride plastic. The cable armor is formed by winding galvanized tapes in a spiral.

Armored aluminum cable, like copper, cannot be subjected to high tensile loads. When the AVBbShv cable is laid alone, fire does not spread along it. Laying armored cable in bundles prevents the spread of fire if AVBbShng cable is used in the work. The fire safety of the product in the abbreviation is indicated by the letter combination ng.

Applicable brands

Laying of 0.4 kV lines is carried out using copper cable VBBbShv or AVBbShv. The cross-section of the models varies between 2.5-240 square meters. mm. The number of cores reaches 1-5 pieces.

For structures with high voltages of 6-10 kV and above, copper products are suitable:

• PvPg is an armored high-voltage cable covered with cross-linked polyethylene-based insulation. The model has a screen, a nominal voltage of 6-10 kV (depending on the instance). The wire can be installed underground and along the bottom of reservoirs. The cross-section of the cores is in the range of 50-800 sq. mm.
• CSPG - the rated voltage is written after the hyphen. The type of cores can be single- (coolant marking) or multi-wire. Insulating layer of impregnated paper. There is a bitumen cushion, a lead shell, and steel wire armor. Section parameters - 25-240 sq. mm.

High-voltage lines are also stretched using AABL cable with aluminum cores. This is an armored product with a rated voltage of 1-10 kV, which is marked after the hyphen in the marking. It has single- or multi-wire type conductors, paper-based insulation (semi-conducting is used in the belt layer). There is also an aluminum shell and two armored steel strips. There are models with a cross section from 50 to 240 square meters. mm.

Products of this type do not require vertical installation; for such tasks, special products with non-flowing impregnation TsAABL-10 are produced. This brand is more suitable for placement in soil with low exposure to corrosion.

Laying and cutting of armored cable

Cutting an armored cable is not as simple as a regular cable. The matter will not end, as always, with simply cutting off the insulation. For proper cutting, it is necessary to expose the ends of the cable and remove layers of insulation and armor to such lengths as to obtain a reliable structure suitable for installing couplings.

You will need scissors for cutting metal strips; they are also useful for thick layers of insulation, although it will yield to a mounting knife. A hacksaw for metal and pliers for removing screens and armor tapes will also be useful. Armored cables are cut with NS (sector) scissors. They are needed for cutting out defective areas and cutting off excess length from the ends.

The lengths of the cable ends after cutting can be indicated in the instructions or documentation for the couplings or special tables from the relevant literature.

Important:

Cable cutting involves the gradual removal of protective covers - layers of insulation, armor, windings, screens. Each of the steps differs in length from the end of the cable, and the edge of the cover on this step is fixed with a steel wire bandage.

The picture shows the cutting steps, and the table shows the lengths corresponding to different cable sections in mm. This is just one example, in reality it depends on the type of cable and the type of connecting or termination, but you can use these data as a guide.

Armored cable is cut in stages

Explanation of symbols:

1. - outer protective cover.
2. - armor.
3. - lead sheath.
4. - waist insulation.
5. — phase insulation (cores).
6. - veins.
7. - wire bandage.
8. - wire bandage.

Famous manufacturers

The average price for the same type of cable from manufacturers is approximately the same. The maximum difference in the cost of products is no more than 20%. Delivery costs, which largely depend on the company chosen, the location of the product warehouse and the location of the customer for the product, have a significant impact on the final bill. Among the most famous and popular suppliers of armored cable are the following:

• Tomskkabel LLC, Sibkabel JSC, Tomsk;
• JSC "Pskovkabel", Pskov;
• JSC "Plant Energokabel", CJSC "Plant Moskabel", Moscow;
• JSC Cable Plant Energia, Proletarsk;
• LLC "Rybinskkabel", Rybinsk.

To reduce delivery time for goods, we keep all popular cable ranges in stock.

Features of laying cables in metal pipes

For wooden buildings (houses, bathhouses, etc.), it is recommended to lay protective pipes made of metal materials. Such materials include: iron or galvanized steel. The use of galvanized products is more preferable, as they have good resistance to corrosion.

Internal wiring in premises can be laid in metal corrugated and smooth pipes

It is recommended to use DKS pipes for laying cables indoors. The trench use of these pipes is undesirable, however, if such communication is temporary, then it can be done in the soil and from the DCS pipe. To connect individual route segments, as a rule, special threaded fittings are used. The use of such couplings greatly simplifies installation and reduces installation time.

In addition, it is worth remembering that the slope of the route is towards the electrical distribution panel. Pipes, as well as the joints between pipes, must be painted to protect communications from corrosion. Such structures are not suitable for indoor work, since painted pipes do not adhere well to concrete poured into the floor.

Comments:

Step

An intelligent article, described in some detail, thanks to the author. But fastening it with tapes to the support every 50 cm is overkill. It is not necessary. According to the PUE, this distance is 100 cm and is sufficient to firmly hold the cable.

Larion

So I counted the current collectors. Can you tell me how much cable power reserve should be taken in order for the whole system to work?

Magomed

Larion, ideally, the more, the better. The more powerful the cable is installed in your home, the less likely it is that it will ever fail. More power means longer service life.

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Corrugated pipes for laying cables in the ground

Particular attention should be paid to corrugated pipes for wiring power lines in the soil. Such products can be of two types:

• unreinforced;
• reinforced.

Corrugated pipes are the best option for laying electrical cables underground

Reinforced corrugated pipes are characterized by increased strength. Strength is achieved thanks to special steel wire, which is equipped with reinforced models at the production stage.

Today, double-walled corrugated pipes are becoming increasingly popular. This product includes the following structural elements: a corrugated outer shell consisting of HDPE and a smooth inner shell made of high-density polyethylene (HDPE). A distinctive feature of such a pipe is considered to be a high coefficient of ring stiffness. Thanks to this, such models are able to withstand heavy loads. In addition, installation of the cable into the pipe is carried out without any difficulties, since the smooth inner wall made of LDPE simplifies the process.

The light weight of the pipe also facilitates its installation, and high thermal stability allows double-walled corrugated pipes to be used in different climatic zones. In addition, the positive qualities of double-walled models include: resistance to the destructive effects of corrosion, resistance to ultraviolet rays and a service life that can reach 50 years (in some cases more).

Main types and types

Before moving on to the main topic of our article, let's figure out what kind of cables there are.

Control cables usually consist of a set of cores from a couple to several dozen. Used for assembling control circuits and connecting groups of sensors and actuators. Can be shielded - this will help avoid interference and give additional strength to the product. An example of such a cable is KVVG - copper with PVC insulation. At the beginning of the marking of such cables there is usually the letter K.

KVVG

Information and signal cables. These include twisted pair and fiber optic. Optical fiber can be single-mode or multimode, depending on its purpose and design. Telephone “noodles” also belong to this class. Twisted pair cables can be supplemented with screens and protective sheaths, like other types of cable products.

Armored twisted pair cable for external installation, self-supporting

Power cables are used to connect electrical equipment to the power supply. If the first letter in the marking is A - for example, AVVG, then the cores in it are made of aluminum. If there is no letter A, for example VVG, then it is copper. The remaining letters tell us about the insulation materials and the presence of additional components. VVG stands for Vinyl-Vinyl-Bare, that is, two layers of PVC insulation and a bare core.

VVG 4×1.5

Power armored is a separate type of product designed for operation in difficult conditions in aggressive cutting or under possible mechanical stress, including in the ground. Information cables can also be protected by armor. They can be either aluminum or copper. An example is an armored copper cable VBBShV with insulation made of cross-linked polyethylene and a sheath made of pressed PVC hose, and armor made of steel tapes, you will learn more about this below.

VBBSHV with five cores

A special word needs to be said about the load-carrying geophysical cable - this is a type of armored product used for research purposes in the oil and gas industry, in marine and geological expeditions. It has another name - logging.

Logging cable

Product parameters

When purchasing a cable, you need to consider the following indicators:

• Rated voltage. The most important parameter, especially for the installation of lines at 6, 10 and higher kilovolts. This indicator depends on the thickness and quality of the insulating layer.
• Cross section is a significant characteristic that affects the power carried by the cable.
• Availability and type of armored coating.
• Screen presence.
• Core flexibility category. It is important when laying the product in small spaces.

The requirements and characteristics of armored cables are set out in detail in the technical specifications and state standards for the manufacture of such products. The standards are presented in the following documents:

• Insulation and sheath thicknesses, voltage tests (GOST 2328686-78).
• Sheaths made of aluminum and lead for power cables (GOST 24641-81).
• Standard for cables VVG, AVVG, AVBbShv, VBbShv (GOST 16442-80).
• Power cables with plastic insulation for rated voltage 0.66, 1, 3 kV (GOST 31996-2012).
• Protective covers of cables, variations, requirements (GOST 7006-72).
• Electrical resistance of the core (GOST 22483-77).

Purpose of armored cables

Modern power cables come in a wide variety. They also include armored cables, which are widely used in the field of energy supply to industrial and civil facilities. Armored power cables - BSK - are distinguished by an external protective coating of increased strength. Typically, wire or steel tape is used for these purposes, preventing mechanical damage and the action of an aggressive environment.

The armored cable is laid in the ground and supplied to buildings, structures, street lighting systems and other objects to supply electricity to them. Unlike overhead lines, BSK laid in the ground is not affected by rain, snow, temperature changes, gusty winds and other negative factors. When laid in a trench, it becomes invisible to others and does not spoil the appearance of the landscape design.

There are certain brands of BSK that are best suited for installation in the ground. The choice of a specific product is influenced by the type and corrosive activity of the soil, as well as general operating conditions. For example, in the presence of acidic and wet soils, their high activity and the destructive effect of corrosion are noted.

Some cables are subject to tensile loads; for such cases, brands with an additional margin of strength are selected. The design of armored cables fully complies with all requirements and technical conditions, so they do not need additional protection during installation work.

Fiber optic communication cables. How it's done

In several of my posts published more than a year ago, I raised such an interesting and somewhat exciting topic for many as backbone fiber optic communication cables, in particular, the topic of “underwater” optics. The information in these publications was incomplete, hasty and scattered, since the articles were written “on the knee” during the lunch break. Now I would like to share structured and, as far as possible, complete material on the topic of optics, with a maximum of tasty details and geek porn, which will make the soul of any techie warm. Inside are diagrams, gifs, tables and a lot of interesting text.

You are ready?

Conditional classification

Unlike the familiar twisted pair cable, which, regardless of the place of application, has approximately the same design, fiber optic communication cables can have significant differences based on the scope of application and location of installation.
The following main types of fiber optic cables for data transmission can be distinguished based on the scope of application:

• For installation inside buildings;
• for cable ducts, unarmored;
• for cable ducts, armored;
• for laying in the ground;
• suspended self-supporting;
• with cable;
• underwater.

The simplest design is for cables for laying inside buildings and unarmored sewer cables, and the most complex ones are for laying in the ground and underwater.

Cable for installation inside buildings

Optical cables for laying inside buildings are divided into distribution cables, from which the network as a whole is formed, and subscriber cables, which are used directly for laying throughout the premises to the end user. Like twisted pair, optics are laid in cable trays, cable ducts, and some brands can also be stretched along the external facades of buildings. Typically, such a cable is led to an interfloor distribution box or directly to the subscriber connection point.

The design of fiber optic cables for installation in buildings includes an optical fiber, a protective coating and a central strength element, such as a bundle of aramid threads. Optics installed indoors have special fire safety requirements, such as non-propagation of combustion and low smoke emission, so polyurethane, rather than polyethylene, is used as a shell for them. Other requirements are low cable weight, flexibility and small size. For this reason, many models have a lightweight design, sometimes with additional protection against moisture. Since the length of optics inside buildings is usually small, the signal attenuation is insignificant and does not affect data transmission. The number of optical fibers in such cables does not exceed twelve.

There is also a kind of cross between a “bulldog and a rhinoceros” - a fiber-optic cable, which additionally contains a twisted pair cable.

Unarmored sewer cable

Unarmored optics are used for installation in sewers, provided that there are no external mechanical influences on them. Also, such a cable is laid in tunnels, collectors and buildings. But even in cases where there is no external influence on the cable in the sewer, it can be laid in protective polyethylene pipes, and installation is carried out either manually or using a special winch. A characteristic feature of this type of fiber optic cable is the presence of a hydrophobic filler (compound), which guarantees the ability to operate in sewer conditions and provides some protection from moisture.

Armored sewer cable

Armored fiber optic cables are used in the presence of large external loads, especially tensile loads. Reservations can be different, tape or wire, the latter is divided into one- and two-layer. Cables with tape armor are used in less aggressive conditions, for example, when laid in cable ducts, pipes, tunnels, and bridges. Tape armor is a smooth or corrugated steel tube with a thickness of 0.15-0.25 mm. Corrugation, provided that this is the only layer of cable protection, is preferable, as it protects the optical fiber from rodents and generally increases the flexibility of the cable. For more severe operating conditions, for example, when laying in the ground or on the bottom of rivers, cables with wire armor are used.

Cable for laying in the ground

For laying in the ground, optical cables with single-strand or double-strand wire armor are used. Reinforced cables with tape armor are also used, but much less frequently. The optical cable is laid in a trench or using cable layers. This process is described in more detail in my second article on this topic, which provides examples of the most common types of cable layers. If the ambient temperature is below -10 °C, the cable is preheated.

In wet soil conditions, a cable model is used, the fiber-optic part of which is enclosed in a sealed metal tube, and the armored wire is impregnated with a special water-repellent compound. This is where calculations come into play: engineers working on cable laying must not allow tensile and compressive loads to exceed the permissible limits. Otherwise, either immediately or over time, the optical fibers may be damaged, rendering the cable unusable.

Armor also affects the permissible tensile force. Fiber optic cables with double-layer armor can withstand a force of 80 kN, single-layer cables - from 7 to 20 kN, and tape armor guarantees the “survival” of the cable under a load of at least 2.7 kN.

Suspended self-supporting cable

Suspended self-supporting cables are mounted on existing supports of overhead communication lines and high-voltage power lines. This is technologically simpler than laying the cable in the ground, but there is a serious limitation during installation - the ambient temperature during work should not be lower than 15 °C. Suspended self-supporting cables have a standard round shape, which reduces wind loads on the structure, and the span between supports can reach one hundred meters or more. The design of self-supporting suspended optical cables necessarily contains a central power element - a central strength element made of fiberglass or aramid threads. Thanks to the latter, the fiber optic cable can withstand high longitudinal loads. Suspended self-supporting cables with aramid threads are used in spans of up to one kilometer

. Another advantage of aramid threads, in addition to their strength and low weight, is that aramid is by nature a dielectric, that is, cables made on its basis are safe, for example, when struck by lightning.

Depending on the structure of the core, there are several types of overhead cable:

• Cable with a profiled core - contains optical fibers or modules with these fibers - the cable is resistant to stretching and compression;
• Cable with twisted modules - contains optical fibers, loosely laid, the cable is resistant to stretching;
• Cable with one optical module - the core of this type of cable does not have power elements, since they are located in the sheath. Such cables have the disadvantage of inconvenient fiber identification. However, they have a smaller diameter and a more affordable price.

Optical cable with rope

Rope optical cables are a type of self-supporting cables that are also used for aerial installation. In such a product, the cable can be load-bearing and wound. There are also models in which the optics are built into the lightning protection cable.

Reinforcing an optical cable with a cable (profiled core) is considered a fairly effective method. The cable itself is a steel wire enclosed in a separate sheath, which in turn is connected to the cable sheath. The free space between them is filled with a hydrophobic filler. Often this design of an optical cable with a cable is called a “figure eight” because of its external similarity, although I personally have associations with overfed “noodles”. "Eights" are used for laying overhead communication lines with a span of no more than 50-70 meters. There are some restrictions in the operation of such cables, for example, a figure eight with a steel cable cannot be suspended on power lines. I hope there is no need to explain why exactly.

But cables with a winding lightning protection cable (lightning cable) can be easily mounted on high-voltage power lines, being attached to the grounding wire. Ground wire cable is used in places where there is a risk of damage to optics by wild animals or hunters. It can also be used on longer flights than a regular figure eight.

Submarine optical cable

This type of optical cable stands apart from all others, as it is laid in fundamentally different conditions. Almost all types of submarine cables are armored in one way or another, and the degree of armor depends on the bottom topography and burial depth.

The following main types of submarine cables are distinguished (by type of armor):

• Not armored;
• Single (one-step) reservation;
• Enhanced (single-layer) reservation;
• Reinforced rock (two-layer) armor;

I looked at the design of the submarine cable in detail more than a year ago in this article, so here I will give only brief information with a picture:

1. Polyethylene insulation.
2. Mylar coating.
3. Double-layer steel wire armor.
4. Aluminum waterproofing tube.
5. Polycarbonate.
6. Central copper or aluminum tube.
7. Intramodular hydrophobic filler.
8. Optical fibers.

Paradoxically, there is no direct correlation between cable armoring and burial depth, since the reinforcement protects the optics not from high pressures at depth, but from the activities of marine life, as well as nets, trawls and anchors of fishing vessels. This correlation is rather the opposite - the closer to the surface, the more anxiety, which is clearly visible in the table below:

Table of types and characteristics of submarine cables depending on laying depth

Production

Now that we have become acquainted with the most common types of fiber optic cables, we can talk about the production process of this entire zoo.
We all know about fiber optic cables, many of us have dealt with them personally (as subscribers and as installers), but as is clear from the information above, fiber optic, especially trunk, cables can be seriously different from what you dealt with in the past. indoors. Since laying a fiber optic backbone requires thousands of kilometers of cable, entire factories are engaged in their production.

Manufacturing of fiber optic thread

It all starts with the production of the main element - the fiber optic thread. This miracle is produced at specialized enterprises. One of the technologies for producing optical filament is its vertical drawing. And this happens as follows:

• At a height of several tens of meters, two tanks are installed in a special shaft: one with glass, the second, lower down the shaft, with a special polymer primary coating material.
• A glass thread is pulled from the precision feed unit of the workpiece or, more simply, the first reservoir with liquid glass.
• Below, the thread passes through a fiber optic diameter sensor, which is responsible for monitoring the diameter of the product.
• After quality control, the thread is coated with a primary polymer coating from a second reservoir.
• After going through the coating procedure, the thread is sent to another oven, in which the polymer is fixed.
• The optical fiber thread is stretched for another N-meters, depending on the technology, cooled and supplied to a precision winder; in other words, it is wound onto a reel, which is then transported as a workpiece to the cable production site.

The most common fiber optic cable sizes are:

• With a core of 8.3 microns and a shell of 125 microns;
• With a core of 62.5 microns and a shell of 125 microns;
• With a core of 50 microns and a shell of 125 microns;
• With a core of 100 microns and a shell of 145 microns.

It is not easy or almost impossible to solder optics with a core diameter of 8.3 microns in the field without high-precision equipment or installing concentrators.
Control of the diameter of the light guide is of great importance. It is this part of the installation that is responsible for one of the main parameters at all stages of thread production - the constant diameter of the final product (standard - 125 microns). Due to the difficulties in welding threads of any diameter, they strive to make them as long as possible. The linear footage of the fiber optic “blank” on a reel can reach tens of kilometers

(yes, exactly kilometers) and more, depending on the customer’s requirements.

Already at the enterprise itself, although this can be done at a glass factory, it all depends on the production cycle; for convenience, a colorless thread with a polymer coating can be rewound onto another bobbin, in the process painting it in its own bright color, by analogy with the familiar twisted pair cable. For what? For the glory of sat... for quickly distinguishing channels when, for example, repairing or welding cables.

Cable making

Now we have the heart of our product - the fiber optic thread. What's next? Next, let's look at the cross-sectional diagram of such an average underwater (yes, I like them the most) cable:

At the factory, the resulting optical filaments are launched into machines, which together form an entire conveyor for the production of one type of cable. At the first stage of production of unarmored models, the threads are woven into bundles, which ultimately constitute the “optical core”. The number of threads in the cable may vary, depending on the declared bandwidth. The bundles, in turn, are wound into a “cable” using special equipment, which, depending on its design and purpose. This equipment can also cover the resulting “cable” with a waterproofing material to prevent moisture from entering and fading of the optics in the future (called “in-module hydrophobic filler” in the diagram).

This is how the process of twisting bundles assembled together into a cable takes place at the Perm fiber optic cable plant:

After the required number of optical fiber bundles have been collected into the “cable,” they are filled with polymer or placed in a metal or copper tube. Here, at first glance, it seems that there are no pitfalls and there cannot be, but since the manufacturer strives to minimize the number of connections and seams, everything turns out to be not entirely simple. Let's look at one specific example.

To create a tube-body, shown in the diagram above as a “central tube,” a huge-length strip of the material we need (steel or copper) can be used. The tape is used so as not to have to deal with all the obvious rolling and welding around the entire circumference of the joint that we are familiar with. Agree, then the cable would have too many “weak” points in the design.

So here it is. The metal strip blank passes through a special machine that tensions it and has a dozen or two rollers that perfectly align it. Once the sliver is aligned, it is fed to another machine where it meets our fiber optic strand bundle. An automatic machine on a conveyor bends the tape around the stretched optical fiber, creating a perfectly shaped tube.

This entire, still fragile, structure is pulled further along the conveyor to a high-precision electric welding machine, which at high speed welds the edges of the tape, turning it into a monolithic tube into which a fiber-optic cable is already laid. Depending on those. process, the whole thing can be filled with a hydrophobic filler. Or don’t flood it, it all depends on the cable model.

In general, everything became more or less clear with production. Different brands of fiber optics, primarily trunk cables, may have some design differences, for example, in the number of cores. Here the engineers did not invent a bicycle and simply combine several smaller cables into one large one, that is, such a backbone cable will have not one, but, for example, five tubes with optical fiber inside, which, in turn, are also filled with polyethylene insulation and, when necessary, reinforced. Such cables are called multi-module

.

One of the cross-sectional models of a multi-module cable

Multi-module cables, which are mostly used for long highways, have another mandatory design feature in the form of a core, or as it is also called, a central power element. The CSE is used as a “frame” around which tubes with fiber optic cores are grouped.

By the way, Perm, the production process of which is presented in the gifs above, with its volumes of up to 4.5 thousand kilometers of cable per year, is a dwarf compared to the plant of the same infrastructure giant Alcatel, which can produce several thousand kilometers

fiber optic cable in one piece, which is immediately loaded onto the cable-laying vessel.

A steel tube is the least radical option for armoring optics. For non-aggressive operating and installation conditions, ordinary insulating polyethylene is often used. However, this does not negate the fact that after such a cable is manufactured, it can be “wrapped” in an armor winding made of aluminum or steel wire or cables.

Reservation of cable with polyethylene insulation at the same Perm plant

Conclusion

As you can understand from the material above, the main difference between different types of fiber optic cable is their “winding”, that is, what the fragile glass strands are packaged in, depending on the application and the environment in which the cable will be laid. If you liked this material, then feel free to ask questions in the comments, based on which I will try to prepare another article on this topic.
Thank you for your attention.

What does an armored cable consist of?

Any cable consists of conductive cores and several layers of diverse sheathing. Copper or aluminum conductors are used for cable cores. These metals have the necessary strength, elasticity and good conductivity.

Power armored cables can be single or multi-core. The conductors in a two-core cable have the same cross-section. In other multi-core cables, one or two conductors have a smaller diameter; they serve as a neutral and ground wire.

The design of armored cables has the following features:

Conducting elements can be single or multiple. In shape they are round, sector, flat or divided into segments.

A cable filler is placed in the space between the conductors, which can be rubber, paper, polymer mass, varieties of rubber and its mixtures with other substances, and even technical oil (it is used to fill the internal space of cables operating under high voltage).

Fillers ensure the tightness of the cable, give it strength and rigidity, and allow the elements inside the cable not to come into contact with each other.

All conductors are combined into a single element using belt insulation made from paper impregnated with a special composition.

A protective shell is located on top of the waist insulation. It is made from rubber, PVC, plastic or metals (steel, aluminum, lead). Thanks to the protective sheath, the cable acquires additional strength, rigidity and resistance to corrosion.

Power cable armor is made of steel in the form of strips or wires. A cable with tape protection made of galvanized or corrugated steel is used for laying power lines, provided that it is not subject to stretching. Corrugated steel armor is also used to protect optical or telephone cables.

Wire armor is ideal protection for cables that will be used underground or in other environments where they will be subject to tensile stress.

A polyvinyl chloride or polyethylene shell is located on top of the armor protection. It blocks access to steel armor from moisture and chemicals that may be in the environment.

The structure of the armored cable is clearly visible in cross-section - each component element is clearly visible and makes the design features of the power cable armoring more understandable.

Design Features

The design of armored cables consists of the following components:

1. Axial central element. Its role can be played by a fiberglass rod or steel rope with or without coating.
2. A copper or aluminum conductor that conducts current.
3. An insulating layer made of polyethylene, PVC or impregnated paper.
4. Copper wire screen or conductive tapes made of paper, metal and cardboard.
5. Another insulating layer.
6. Tape spiral armor. It is arranged in several layers with overlap at the joints.

The end of the cable is protected by a coupling, which protects the insulation of the product from damage and prevents the wires from mixing with each other. This element is also used in the installation and repair of armored wire. The couplings are filled with dielectric compounds, for example, bitumen.

Insulation requirements increase with increasing cable voltage. Air entering the connections of high-voltage networks can lead to its ionization and the occurrence of discharges.

Laying process

Preparing a trench for armored cable

Before laying the cable in the ground, prepare the route in which it will be laid. When designing it, you need to take into account everything possible with any engineering networks and communications. After this, you can proceed directly to the trench itself. If the cable is laid under a road, it is necessary to immerse it to a depth of at least 125 cm. If there is free ground on top of the trench without loads, for example a lawn, 90 cm is sufficient.

Please note that even in situations where the trench design is based on a geo-base diagram, you should dig carefully. There are often cases when you can come across engineering systems incorrectly marked on the diagram

A sand cushion up to 15 cm high should be poured onto the bottom of the dug trench. This is necessary for additional protection of cable lines and markings. The sand must be moistened with water and compacted well.

Pad

Laying cables underground, as a rule, means that an armored conductor is used, protected from mechanical stress and rodents. If an unarmored electrical cable is used, it is necessary that its brand meets the increased requirements for resistance to mechanical and thermal stress. It is for this reason that copper armored cable is most often used.

The cable itself is laid inside a sand cushion, on top of which a layer of soil approximately 15-20 cm thick is then poured. This should also be compacted. On top of this layer, protection is laid out from brick, asbestos cement, reinforced concrete slabs or any similar material.

A warning tape is placed on top. According to the requirements of the PUE, it must be located strictly above the cable throughout the entire length of the trench, and the signal inscription must be located on top. After this, the trench is backfilled with a reserve. This is necessary because the soil sags over time.

The PUE also requires that at each stage of laying and backfilling lines, its functional characteristics are checked. To do this, you can measure the insulation resistance.

It is also recommended that after laying the cable, you take a photograph of its location. The photo will be convenient to use if it is necessary to dismantle or repair grounding cables and other purposes. Many people ignore the requirement to lay warning tape on their property when supplying electricity to a bathhouse or cottage. This is against safety regulations, but with photographs it at least provides some assurance about the exact location of the cable in the future.

Reservation with steel tapes

The use of low-carbon steel armor allows you to protect the cable from mechanical stress, however, an important condition for the operation of such products is the absence of stretching during operation. In accordance with GOST 3559-75, several types of tapes can be used as armor:

A - with a galvanized surface (for example, Apple tape for flat armor, having a layer of zinc),

B – without corrosion protection,

B – using a bitumen layer.

The destruction of such tapes occurs under the influence of a tensile force of over 275 MPa, with an increase in the length of the wire by no less than 30%.

Armoring of the cable, which is laid in open space and in the ground, occurs using tapes with a thickness of 0.3 to 0.8 mm, with a width of up to 60 mm. Such armor is applied sequentially, in two layers, with the top strip applied to 25% of the width of the bottom; the gap distance between them can be up to 33% of the armor thickness.

The strength of cables of types BvG, BbG, BG, BlG and BpG can be increased by galvanized armor or steel tape B with a bitumen layer. Also, these products can be armored with steel wire with a galvanized surface, and the rod can have a diameter from 1.4 to 1.8 mm.

Cable and wire products of increased flexibility, operated in conditions involving the risk of damage under pressure, which is applied towards the radius, are covered with armor made of tapes 0.5 mm thick and 10 mm wide. The use of protection for KPBK cables requires additional S-shaped profiling - in this case, the edges of both tapes are interlocked in a “lock” and do not separate even when the wire is bent.