How the cable is pulled. Cable pulling is an important tool for SKSnik! Installation of electrical wiring in corrugated open method

Rarely does an installation or construction team manage without an ultrasonic testing device (cable laying device). This is an installation tool used in the construction of electrical, telephone, computer, intercom and other systems. A cable pull (a common and more familiar name for a device) is extremely necessary when laying wires through ducts, voids, pipes, metal hoses, and panel cabinets.

General description of the device

A broach (also known as an ultrasonic device, boom, probe, conductor, rod) was invented for tightening cables or wires into various communication channels. It looks like a durable, flexible, indestructible structure. Some types of devices are capable of self-extending.

The broach has an internal cord. It is formed by the rod round section. The compact core consists of unidirectional reinforcing fibers, radial threads that crosswise envelop the longitudinal reinforcing fibers. This is the main part of the device - the rod. It is made from various materials.

The rod is covered with a special braid (shell), which serves for ease of operation and increases the service life of the device. A long rod is wound onto a reel and placed on a cassette in a coil. The cassette is rotated, as a rule, manually. The rod is supplied with removable tips.

The normal operating temperature range of the product is from -15°C to +50°C. The average service life is 1.5 years. But the safety of the rod depends on the intensity of use and conditions of use.

Types of broaches

Cable pulling can be done using various types devices. They are classified according to the material used to make the interior. The following types of broaches are distinguished:

  • fiberglass;
  • steel;
  • nylon.

Fiberglass broaches have the highest rigidity. Due to the structural characteristics of fiberglass, they tend to straighten. This allows the cable to be pulled through small holes, dropped ceilings. However, handling such broaches requires care. Fiberglass is a fragile material and is susceptible to bending at low degrees.

A steel broach is formed by metal wire or tape wrapped in a nylon sheath. Steel material provides better bending and tensile strength of the broach. This type of device is very effective for pulling cable through L-shaped bends in ducts.

Closed channels (metal hoses, ducts, pipes, etc.) can be passed through with nylon broaches. The device has a particularly flexible guide. It can be combined with a pressed-in brass tip. Thanks to the dielectric properties of nylon, it is safe to pull near live cables.

Device contents

Traditionally, an ultrasonic tester consists of a set of tips, a glass rod, and a trolley. Richer configurations may include additional accessories. Manufacturers offer devices for gripping broaches, a special spring for quickly clamping cables, and gel lubricants.

Depending on the length of the rod, it is folded into a circle or wound onto a reel. More massive reels are mounted on a trolley, which has wheels for convenient and quick movement.

Marking numbers indicate the diameter of the rod and its length. The diameter of the rod is measured in millimeters and can be 3.5 mm, 6 mm, 9 mm, 11 mm. For example, the numbers 11/150 mean that a rod with a diameter of 11 mm and a length of 150 m is wound on the reel.

For ease of tightening cable conductors, the rod is terminated on both sides with lugs. They serve for ease of gripping and tightening the wire. Thus, a tip with a double loop (cable stocking) is capable of quickly and efficiently gripping a cable weighing up to 5.5 tons and holding the conductor in vertical plane for installation.

The tips are threaded, allowing you to attach various devices. These can be guide heads, connecting tubes, rotation compensators, etc. The most widespread are 2 types of tips: with a guide head and with an eye for attaching the wire being pulled.

Hydraulic cable jacks, cable guide rollers, protective cable entries, and cable bends (elbows) can be used as auxiliary ones. Various lubricants - gels for lubricating the cable - reduce traction forces and protect the conductor from mechanical damage.

Where is it used?

To create complex lines or systems in hard to reach places installers and builders actively use the device for pulling cables. The device helps overcome obstacles in the way various types voids:

  • pipes;
  • boxes;
  • channels;
  • metal hoses;
  • floor panels.

Functionally, the use of ultrasonic testing is comparable to the use of a probe. The tool is used to insert cable and wire products into the desired work area.

The cable pulling device is used for:

  • creating an electrical wiring line;
  • telephone or computer communication equipment;
  • installation of intercoms;
  • formation of video and audio systems;
  • equipping security and fire alarm systems;
  • installation in suspended ceilings, under the flooring.

Ultrasonic testing is used when it is necessary to stretch a wire or cable inside a closed cavity. First, the channel is passed through with a rod. Then a cable (wire) is attached to a special attachment. After fixing the cable, the rod is pulled back, pulling the cable through the internal space of the channel.

Advantages of modern devices

Development latest technologies leads to constant improvement of ultrasonic testing tools. Modern device for cable pulling, it is often made from polyesters (polyesters).

Initially, polyester fiber has a number of undeniable advantages. The material is durable, wear-resistant, and slightly wrinkled. Therefore, the use of innovative materials and technologies provides a number of advantages for modern ultrasonic testing.

The latest cable pulling device features exceptional anti-friction properties. The spiral shape significantly reduces the contact area.

High quality manufacturing is guaranteed by imported raw materials supplied by leading European manufacturers. This results in a 50% reduction in friction coefficient compared to nylon counterparts.

Mini-ultrasound cable puller made of polyester is distinguished by its special flexibility and spring force. To these qualities are added the minimum bending radius, high strength to break. Unlike fiberglass, polyester tools do not break and create a super-strong connection based on the “broach-tip” principle.

Made from polyester, the cable pulling tool is resistant to ultraviolet radiation, various weather conditions, and alkaline and acidic solutions. Devices made from this material are not subject to corrosion and have good dielectric properties. Color coding Provides easy size identification and navigation in cable ducts, pipes, tunnels.

While laying cables indoors usually does not cause problems for installers, laying cables between buildings over the air is usually more labor-intensive.

Communications between houses can be laid in two main ways: underground and by air. Each of these methods has its pros and cons. This article describes a method for laying cable over the air. The advantages of this method include the ease of installation (compared to the installation of underground communications); it is not always possible to lay underground communications; the length of the cable connecting houses is much longer than in the case of an air connection. The disadvantages of laying by air include exposure of air communications to static electricity and lightning discharges, severe weather conditions, which can lead to premature failure of the cable, if the outer insulation of the cable is damaged due to friction of the cable in contact with other objects, or cracks occur due to weather conditions, the cable picks up moisture and causes equipment failure ( in this case, only replacing the cable can help). Let's consider connecting two houses by air. Hereinafter, we will agree to call such a connection an air connection.

Fig.1. Two houses connected by air.

In the figure: 1 - houses being connected, 2 - cable, 3 - information cable (twisted pair). This is a fairly rough outline of what should happen as a result. So, if you use twisted pair without a cable inside, then the use of a cable is simply necessary (wind, stuck wet snow, ice create enormous loads, the twisted pair cable is not designed for them). It is best to use insulated steel wire as a cable. The cross-section of such a cable with a reasonable air length (less than 80 m) is 1 - 1.5 mm2. Insulation is necessary to prevent corrosion, which can literally “gnaw through” a steel cable of such a small cross-section in just a year. It is necessary to attach the cable to the house to something durable (iron fittings, masts of other cables, etc.). Here the next nuance appears. It is necessary to prevent the steel cable from touching the metal fittings on both houses at the same time. Houses have different potentials, and therefore current will flow through the cable, producing interference on the twisted pair cable, some others are also possible unpleasant consequences. The cable must be grounded. Of course the cable needs to be grounded. It is possible on the one hand. But this will not be the best option, by far the best option the cable will be grounded on both sides, but it is necessary to either ground it on one side through a container (hard on the other), or break the supporting cable in the middle using a dielectric (for example, from a textolite plate).

Now about the twisted pair cable. In our latitudes, a cable located in the open air finds itself in very difficult conditions. The cable stretched between houses is in particularly difficult conditions. Therefore, I recommend using twisted pair cable with special insulation for the external laying for the air. Ideally, such a cable will be filled with a compound (hydrophobic). The use of shielded cables, in my opinion, is inappropriate. A screen will not prevent the accumulation of static electricity in a cable, but cables with a screen are much more expensive. In order to save equipment connected to the air from static electricity discharges and thunderstorms, it is necessary to use special devices, so-called lightning protection.

So let's get back to the air lining. The twisted pair cable must be attached to the cable in advance. Any non-conducting material that is not exposed to water and weather conditions can be used as fastening elements. It is most advisable to use nylon ties. Using nylon ties (or other devices), the twisted pair cable is attached to the cable, and it is recommended to fasten the cable and cable with ties every 50-70 cm. It is necessary to control that the cable sag slightly, otherwise it will turn out that the cable is also held by the cable. But at the same time, it is necessary to reduce the sagging to a minimum (in Fig. 1 there is a very large sagging, made solely for the clarity of the picture). It is necessary to tighten the ties firmly, excluding any sliding of the cable relative to the cable, but it is necessary to avoid damaging the cable by very tightly tightening the fastening element (it is necessary that the contact surface of the fastening element is flat and the width of the element is at least 5-7 mm).

So, now let's move directly to the sequence of actions when laying the cable:

1. First, purchase a cable, cable, fasteners (nylon ties, etc.). The length of the cable is not less than (b+l), where l is the length added taking into account the sagging of the cable and the attachment to the house (Fig. 2).


Fig.2. Schematic plan of the air.

2. Next, on the roof of house 1 we roll out the cable. We measure the length of the wire that is required from point A to the equipment connected in this house (of course, if the cable length does not limit it, it is better to give a reserve) and mark point A on the cable. Find point A on the cable. (we measure the distance from the attachment point at home 1 to point A). We lay the cable next to the unfolded cable (point A of the cable to point A of the cable). We measure the distance (a + d) from point A of house 1 on the cable (d takes into account that, firstly, the cable will sag a little, and secondly, that points A of houses 1 and 2 are located at some distance from the edge of the house). We fasten the cable to the cable along the resulting segment. Person 1 and person 3 tension the cable (Fig. 3), person 2 makes the fasteners. Make the sagging of the cable relative to the cable minimal.


Fig.3. Technology for attaching cables to cables.

3. So, our air cable is almost ready for installation; part of the free cable that will be laid around house 2 is carefully twisted into a coil and attached to the cable with tape (this is done so that the cable does not interfere during installation).

The cable is now ready. We can continue.

The last iteration of cable tension between two houses can be performed in two ways: 1. By pulling the cable through the ground and its successive tension from the roof of house 1 2. By shooting from the roof of house two, a dart with a fishing line is thrown onto the roof of house one (using a crossbow or a special gas guns), to which one end of the cable is tied on the roof. After which the cable is pulled out by the shooter from the roof 2.

Detailed description of method 1.

We need two “buffer” cables (or rope, nylon thread, etc. the main thing is that it can withstand the weight of the cable and the supporting cable). We securely fasten one end of the cable to house 1, attach the second end of the cable to our buffer cable 1, and lower the buffer cable 1 down from house 1 (Fig. 4). Then we move the end of this cable to house 2 (we carefully go around trees and other high obstacles).

So, we have reached house 2. The end of cable 2 is lowered from house 2. The ends of the cables are fastened together and we begin to tighten the fastened cable onto house 2. Pull, pull, pull, pull in short, pull the end of the cable with the coiled cable onto house 2. Pull the cable, but not like a string, let it sag a little. We fasten the cable at home 2, lay the cable, and ground the cable.

Communication cables are like arteries through which information flows - the lifeblood of our society. A modern city dweller, left without communication, feels blind and deaf at the same time, and therefore, when choosing a provider, a person pays considerable attention to its reputation in terms of the reliability of its networks. Accordingly, the quality of network installation affects their reliability, that is, the reputation of the provider, and therefore the number of its subscribers and the income that these subscribers bring to it. This article was written to reveal some of the nuances of cable laying - some tricks of installers, as well as some mistakes. As experts, we invited installers from one of the oldest providers in Yekaterinburg - the Kabinet company. These people have been working on Yekaterinburg roofs for many years, so it is difficult to find better consultants in the field of cable pulling.

So, the roofs of Yekaterinburg. Some time ago, during the time of a huge number of pioneer nets, a mass of people appeared on the roofs of our city pulling copper, and later optical cables. As a result, some roofs now have a veritable web of cables from a variety of providers. Since the cable was not marked before, it is now no longer possible to establish the identity of some links - some of them have long been dead, but no one is in a hurry to remove their used cables. Now all serious providers mark their cable. Some use tags for these purposes, others mark the cable itself.

In addition, providers are currently trying to maintain all their links in one large bundle, and not distribute them haphazardly across the entire roof. In new houses, where a smart HOA rules the roost, all operators are allocated certain points for cable entry and exit, and sometimes the entire route along their roof is marked. And they don’t give permission for laying; if the provider does not agree to their conditions, the provider is prohibited from laying. As a result, in such houses, trunk and house cables from several operators can run in touching unity in a single large bundle. Although, in order to avoid unnecessary dominance, many HOAs try not to allow a large number of cables into their homes, not only out of a desire to get a kickback, but also not wanting to clog their risers and roofs with numerous cables.

So, on the one hand, the cable is protected from friction by the corrugation, on the other hand, it will soon wear out from friction and temperature changes. And it will be difficult to replace her. The slack that the installers left during the installation to reduce friction seems unnecessary - in winter, icicles are guaranteed to form on it. Wouldn't it be better to make the transition along a metal cable, leaving slack only at the bend line at the edge of the roof? We'll talk more about ways to protect cables from friction below.

Now the input - two cables wrapped in corrugation enter one hole in the wall. The edges of the corrugated tubes are sealed with sealant. But that section of the cable that directly passes through the wall is not protected by anything other than its own insulation. We make an allowance for the aforementioned slack, which gives windage in the wind, and we get the friction that will certainly arise in the hole. Could it be possible to pass the same corrugation through the same hole in order for the cable to sit more tightly in the hole and receive additional protection from friction?

Another input method is via dormer windows and attics. It is immediately worth noting that no one intended the dormer windows for laying cables. When old houses were built, these windows were usually made of wood, but over time the wood rotted and was replaced by iron.

In one case, the fastening runs parallel to the cable, preventing it from bending. In another, the same fastening leads to a break in the cable. Here the installer himself didn’t think enough.

Wire is another matter - the climate is not terrible for it. And not to say that working with wire is much more inconvenient than working with ties. To illustrate his theory, he showed a "trick" of the Kabinet installers - a proprietary wire tie, so to speak. The end of the wire is wrapped into a loop with side cutters, the other end of the wire is threaded into this loop and voila:

Pulling the cable along the roof itself also requires considerable effort from the installer, and he also has to work with his head. On the one hand, there is a technology according to which cables must be pulled over roofs using special masts that have special places for attaching couplings, and space for technological reserves, and special guy wires, of which there must be at least four, and they must diverge in different sides for greater mast stability.

But technology is technology, and shortcomings occur even among those who install these masts (and there are few such providers in our city). Pay attention to the lower part of the mast. If everything is done correctly, then the mast should have not four, but eight guy wire holders - equally distributed in the upper and lower parts. But the installers of this mast did not go for such luxuries - limiting themselves to only four guys in the upper part. As a result, the top of the mast is quite securely fixed, and the lower one will sooner or later begin to move.

The mast looks new - it hasn't been standing longer than a couple of months. And due to the lack of fixation at the base, it is already tilting. Moreover, on top part This mast is pressed by the weight of the coupling and technical reserve. As a result, this mast can be brought down with a light kick to the base. But even without a kick, such a design will not last very long. Moreover, the stretch marks in the upper part also do not inspire confidence, because they are secured like this:

That is, the cable mount is simply driven into the ventilation shaft pipe. Firstly, this destroys the pipe itself, and the local housing office workers, if they climbed onto the roof, are unlikely to be happy with this picture. Secondly, this method of fastening in itself is short-lived - a strong gust of wind will sooner or later pull out the cable along with the fastening, and then what? Re-hammer it into the pipe? Until the next gust of wind? So soon the pipe will only be holes...

More The right way the mount looks like this:

Around ventilation pipe or other stable structure firmly standing on the roof, a metal cable or wire of considerable cross-section is wrapped around it. You can safely attach the mast guy wires to the resulting loop, although most Ekaterinburg providers attach the cable directly. This solution is much more durable and does not harm the structure to which it is attached.

It is known that a significant part of the masts belongs to Rostelecom (formerly Uralsvyazinform), which inherited these masts along with wired radio networks. Other operators also install their own masts to a greater or lesser extent. Rostelecom masts are actively used by other providers to extend their lines.

Unfortunately, not all installers do this in compliance with technological standards - here is an example of how RT-Ural telephone masts cannot be used.

If RT-Ural installers find themselves on the same roof, they will probably simply cut off someone else’s cable that was thrown through their mast with such impudence. If I were them, I would cut them off.

However, Rostelecom masts are not found everywhere. In their absence, many Ekaterinburg providers are stretching using dormer windows, ventilation shafts and, in general, any large roof structures suitable for cable fastening

It is still worth remembering that using ventilation pipes when pulling cables is not always correct. Here are cases of obvious violation of any laying technology:

In the first case, the cable is attached to an old rusty ventilation pipe, which is already tilting even without additional load. It is unlikely that much time will pass before the cable, swaying under the influence of the wind, tears out this pipe. And the cable will remain without support and the housing office will be saddened.

In the second case, the cable is routed directly through the ventilation pipe. Through this hole, warm air flows from the apartments come out - including hot air generated above kitchen stoves residents of this house. Under the influence of the jet warm air Any insulation will sooner or later begin to melt.

It would be more correct to choose strong and massive superstructures on the roof as a support for the cable and lay the cable not through them, but along the outer perimeter of such superstructures. To attach the cable to their walls, methods that do not lead to damage to the superstructure are acceptable - the same wire loop around the superstructure. The cable can be secured to massive, durable superstructures using spacers:

What you definitely shouldn’t do is simply throw the cable through such add-ons. Equals Rubbing the cable against a corner will damage it.

The technology used by Kabinet's installers provides for transitions in such cases - the guys make one of them right in front of me. In a good way, every time the cable can come into contact with the corner of such a booth, the edge of the roof or the corner of a ventilation pipe, you should put here is the transition:

That is, if during pulling there is some obstacle that the cable will rub against, then an insert of a metal cable is made in the area in contact with the obstacle, and the cable makes a small wave. This allows you to go around the dangerous area. In this way, you can bypass almost any potentially dangerous areas, be it the corners of buildings or roof railings. Such a transition will not take much time - the experienced Kabinet "sheep in my presence did it in about five minutes. Those who neglect this simple solution, risk one day seeing your cable frayed:

Rubber gaskets and corrugations do not cope here, since very often they either fray themselves or slide off due to friction:

Corrugations and rubber gasket tubes are good for protecting a cable from another cable. In conditions where the entire roof is entangled with cables, situations inevitably arise when the cables cross and rub against each other. This is where the corrugated tube is just right.

Any building in the modern world is literally entwined with hundreds of meters of cables for various purposes. For insulating conductors in areas where visual appeal is not required, but there is a need to protect cables from exposure environment Corrugated tubes are used.

What is corrugation

Corrugation can be made of polyvinyl chloride, polyethylene, polypropylene, polyamide or metal. It has the shape of a corrugated pipe, inside of which there is a thin metal wire designed to make it easier to insert the cable into it.

Corrugated polyvinyl chloride has become the most popular when laying electrical wiring, as they are cheaper and weigh less than their metal counterparts. In addition, this material reduces the likelihood of a fire in the room due to a short circuit in the conductors, since it provides additional insulation to the cable and has self-extinguishing properties.

All corrugated pipes are characterized by a long period of operation, retain their properties throughout their entire service life, have high resistance to mechanical loads, are made of environmentally friendly materials that are safe for human health, and are lightweight, which makes installation and transportation easier.

To accommodate cables of various cross-sections, the corrugated tube can have a diameter from 16 to 63 millimeters.

Scope of application of corrugated pipes

Corrugated pipe can be used for laying hidden and open wiring both in ordinary residential and industrial, technical, administrative premises. The corrugation can be attached to walls, ceiling or floor. It is used for laying not only power cable lines, but also for installing cables for communication networks.

The advantage of corrugation over installation in a cable channel, which is attached only to a flat and smooth wall, is the possibility of installation on any surface. The flexibility of the tube allows it to be rotated at almost any angle or even twisted.

It is important to remember that the polyvinyl chloride from which it is made most of light corrugation, sensitive to sudden temperature changes, high humidity And ultraviolet radiation sun, so such products should be used for pulling cables only in enclosed spaces. For the installation of external wiring, there is a separate heavy type of corrugation, which has increased strength and high moisture resistance.

For convenience, the color of the corrugated pipe is selected in accordance with its purpose. There is a common European standard Whereby:

  • White pipes are used for installation of computer networks
  • Gray pipes are used when laying electrical wiring
  • Brown or black are used when connecting household appliances
  • Greens protect telephone wiring
  • Red ones are used when laying external wiring
  • Yellow ones are used in gas supply systems
  • Blue for water supply pipes

Inserting the cable into the corrugation

Work on laying cables in a corrugated tube should be carried out by a team consisting of at least two people. This is due to the features of the following algorithm of actions, which explains how to correctly pull the wire through the corrugation.

First, you need to remove the end of the wire from the structure and connect it to the cable being mounted. To do this, make a hole in the wire winding, insert the wire into it and secure it securely by carefully twisting it. Next, you need to level the corrugation along its entire length and you can start pulling the cable. One worker must hold the edge of the corrugated pipe from which the wire is inserted, and the second must pull out the steel wire from the other side, thus pushing the cable into the corrugation. Often the conductor gets stuck inside the corrugated pipe; this situation arises due to weakening of its tension or the appearance of bends, so the condition of the corrugation should be monitored until the end of the pulling process.

A fully extended cable should be fixed by tightly wrapping it to the pipe, this is done in order to avoid movement of parts of the structure relative to each other.

It is worth noting that there are corrugated pipes on sale that are not equipped with a steel probe; the price of such products is much lower, but pulling cables through them is not a simple, labor-intensive task. In these cases, one worker must push the cable, and the rest must ensure its progress by deforming the corrugated pipe at the location of the end of the cable.

Corrugated cable laying

Laying corrugated cables along the wall can be done using special clips, the diameter of which is selected in accordance with the cross-section of the corrugated pipe. This method of fastening looks the most aesthetically pleasing, but in hidden places, as a rule, staples made of metal packaging tape are used, secured with dowel nails.

Inexpensive couplings are used to join pieces of corrugation. If on this area If there are no cable connections, then the place where the pipe is attached to the coupling can be sealed with a sealant; otherwise, more reliable insulation methods should be used. For passages through walls, special sleeves are selected, which are also sealed if necessary.

When laying, it is very important to avoid bending corrugations of less than the permitted radius; such information is usually indicated by the manufacturer on the product packaging.

Installation of electrical wiring in a corrugated

When installing electrical wiring by any method, a universal requirement is the use of terminal strips, soldering, crimping or brazing to make connections. The contact points of the conductors must be accessible for inspection, so if the cables are placed in corrugated pipes, the connections should be placed in distribution boxes.

Another requirement of the PUE is the need to separate the main and backup channels into different channels. cable line, cores of working and emergency lighting, that is, the corrugations with these wires must be geographically separated.

Plastic corrugation, which is not fireproof, is allowed to be placed in the grooves of walls consisting of concrete, bricks or other fireproof materials. In all other cases, for example, when installing hidden wiring in wooden houses, fireproof gaskets (cement, plaster, asbestos) should be used to separate the corrugated tubes from the surface at a distance of at least 10 millimeters. When laying plastic corrugation on a fireproof surface, the distance from combustible areas should be more than 10 centimeters.

Features of installation of electrical wiring in corrugated open method

When installing open electrical wiring in accordance with the requirements of the PUE, the distance from the corrugated pipe to the combustible base must be at least ten millimeters. It is clear that, for example, in a wooden house such a condition cannot be met without the use of special gaskets. Penofol, which has the most balanced combination of price and quality, is often used for such purposes. Please note that to comply with the requirements fire safety the gasket should protrude 10 mm in all directions from the border of the plastic corrugation.

According to the PUE, installation of open electrical wiring in rooms at a height of two meters above the surface is allowed. The use of corrugations allows you to circumvent this limitation, since they all have the necessary degree of strength to protect cables from damage by penetrating objects with a diameter exceeding 12.5 millimeters (IP20). Indeed, according to the same PUE, the fulfillment of this condition allows the installation of open electrical wiring in rooms at any height, but it should be taken into account that wiring of this type cannot be used on roofs, with the exception of the place where the cable enters the building.

Features of using metal corrugation

The metal corrugation must be connected to the grounding circuit of the lightning rod and also protected from corrosion. The resistance of the grounded corrugated pipe to the point of exit to the bus should not exceed 10 Ohms.

It is laid in such a way as to avoid places where moisture accumulates, and the joints connecting to distribution boxes are necessarily insulated using sealant or standard means.

If these requirements are met, it is permissible to lay the cable in metal corrugation along the walls of buildings both outside and inside. If the sealing conditions are not met, then even a small amount of water entering the system can lead to complete failure of the line.

It is prohibited to use metal corrugation in bathrooms and bathrooms, except when passing under the floor and covering it with a grounding mesh.

Repair of corrugated tubes

If an already installed corrugation is damaged, the plastic corrugation is welded with polyethylene, and the metal corrugation is soldered with a special acid.

Video on the topic

For various reasons, it is not always possible to conduct underground electrical cable to an object that needs to be supplied with electricity. In such cases, the technology of laying cables or individual wires through the air on a cable is successfully used. In the article we will look at how to install and lay a cable on a cable to a house or garage, and what types of fastening are used.

Scope of technology

Such technologies are used only in electrical networks with a voltage not exceeding 1000 volts, the requirement of the PUE is Chapter 2.1. In most cases, the laying of cables on cables is used from buildings or power lines to individual structures over short distances. Where installation of power line supports or digging trenches for cables is impossible according to technical specifications production during the operation of facilities, or unreasonably in terms of the volume of work performed, is expensive from a financial point of view.

IN production workshops, warehouses, structures with large areas, high ceilings, for lighting the best option is the use of these technologies. Cable cables are used for electrical networks of street lighting in certain areas.

For private home owners, this wiring method eliminates the time-consuming work of digging a trench. It’s easier to stretch a cable through the air from the distribution board in the house to outbuildings:

  • workshop;
  • summer kitchen;
  • gazebo with barbecue;
  • chicken coop;
  • bathhouse and other possible structures in the courtyard of a private household.

Cable wiring allows you to conduct light three-wire wires for electrical consumers of low power and cables with large cross-section wires for power supply of powerful household appliances. Before proceeding with the installation of cable wiring, preliminary calculations are required.

Preliminary measures before installation

At the first stage, it is necessary to determine how much power will be consumed by electrical appliances in the structures that are planned to be provided with electricity. Based on the power consumption, the cross-section of the cable wires is calculated, its length and weight are taken into account. These parameters determine which fasteners to use, the diameter and material of the cable. To calculate power consumption and cable cross-section, a more detailed study of a separate topic is required. In simplified form it looks like this:

  • The power of all electrical appliances is summed up, which are supposed to be used in the calculated network. The power of each device is indicated in product passports or nameplates on the housing. The simplest example of a lighting lamp is always written 40 on them; 60; 75 or 100 or more watts.

∑Р = P1 + P2 +…Pn = 3.7 kW. (3700 W) – Total power.

  • Determine the maximum possible current in the circuit

I = ∑Р/ U=3700 W/220 V = 16.8 A. – Maximum current.

U – network voltage.

  • To determine the cross-section of wires in a cable, use the table

In our case, we choose a maximum current value slightly greater than 19A, taking into account that in the future additional Appliances. According to the table, we obtain a power of 4.1 kW, which corresponds to a copper wire cross-section of 1.5 mm. You need to understand that the cross section is not the diameter, it is calculated using the formula:

Experienced electricians are well aware of the standards of cables and wires and determine the cross-section by eye. For ordinary consumers, there are tables for determining the cross-section by diameter, it is enough to measure the diameter of the wire with a micrometer or caliper and determine its cross-section using the table.


  • Next stage preliminary work, cable length measurement from the distribution board in the house to the switchgear ( switchgear) on the building to which the cable structure is stretched. This can be done with a regular tape measure,

Tip #1. Be sure to take into account the cable reserve for cutting and connecting to the control panel; add approximately 30 cm at both ends.

Selecting the diameter and material of the cable

Determine the weight of the cable and other elements that will be attached to it. If the distance between the supporting fasteners is 5-6 m and the weight of the wire is not significant, you can stretch galvanized steel wire with a diameter of 2-3 mm. When the distance is more than 10 m, the cable is heavy, especially if the cable structure is used with lighting elements, galvanized steel cable with Ø 4-6.5 mm is used. Such a cable will withstand any cable with a wire cross-section of up to 10 mm/sq.m; larger cables are not used in private households due to limited power consumption. You can also hang up to 5 pieces on such a cable. lighting lanterns in a lightweight housing.

The cable can be wound and weighed on ordinary scales, or calculated by knowing its brand according to the characteristics table, which is included with the sale. The weight of the cable per 1 m is indicated, you need to multiply the specified weight by the number of meters you get total weight piece, which is used for fastening to a steel cable.

For domestic conditions, in order not to waste money, you can hang the cable that was used for hidden wiring. In order for the insulation to last longer, lay it in a corrugated pipe; its weight is not significant. There are reference tables indicating the brand and weight of the cable. You can look it up on the Internet; some sites have calculators for calculating the length and weight of wires and cables.

Tip No. 2 Use the calculator on this site http://kabelves.ru/


 Table indicating the cable brand and weight in kg. by 1 meter

For high current loads, it is better to use special cables for overhead cable structures:

  • AVT, AVTS, APT already have a built-in supporting steel cable;
  • AVRG, ANRG, APVG, AVVG are suspended from a supporting steel cable.

Supporting and tensioning elements of cable wiring

These products are installed on the walls of buildings, structures between which tension is stretched. Depending on the material and diameter of the cable, the fastening design is selected:

  • Tension bolt, hook and tension anchor are used for flexible stranded cables industrial production bearing heavy loads, rolled wire with a diameter of up to 6 mm can be used.
  • Anchors for tensioning strings with a small diameter are designed for light wires with a cross-section of up to 6 mm at a distance of up to 10 meters, without elements lighting fixtures.
  • Anchors for industrial cables and wire rods are capable of supporting heavy cables and lighting elements at a distance of up to 12 m without additional supports.
  • Fasteners for stringing parallel lines are often used for dual purposes, for power supply to structures and placement of lighting lanterns. A power cable with a wire cross-section of 10 -35 mm/sq. is laid along one cable; on the second, lighting fixtures, distribution boxes with copper wire 2.5 – 4 mm.

All these designs have individual characteristics when installed on the walls of buildings.

Requirements for installation of end fastenings and installation features

Never attach end pieces to decorative cladding buildings and roofing details. Devices designed for heavy loads are fixed on both sides load-bearing wall steel plates fastened with through bolts. As shown in the picture for the tension bolt with hook. They must be located above pedestrian passages at a height of at least 2.7 m, and above vehicle passages at least 6 m. Anchors for strings with lighter loads can be secured with simple anchor screws for concrete.

Ideally, tension anchor devices are installed in the wall during the construction of buildings according to the project. In practice, this is not always provided for; then you have to drill into the walls with a hammer drill. Under the end fastening, a metal plate with a bolted contact is attached at 20-30 cm for grounding the cable. It is connected by a welding joint to rolled wire with a cross-section of at least 16 sq/mm, which goes to the common ground loop. In some cases, grounding is performed with a separate copper wire with a cross-section of at least 2.5 sq/mm using bolted connections.


 Laying the cable on a cable when connecting to the wall

Installation and tension of the cable

After installing the terminal fastenings, the cable is attached to the guy wire on the ground, lighting fixtures with junction boxes are fixed and connected. Assembled structure is delivered to the installation site and unwound along its entire length from one mounting anchor to another.

The length of the cable must be at least 2 m greater than the distance between the end anchors. The reserve will be needed to seal the fastening to the terminal devices and bring the ends to the grounding terminals, which are located below the anchors. The end loops of the cable are attached to the tension anchors, after which they regulate the tension. The tensile force should be up to 100 kg/cm for light structures with cables with a cross-section of 4-10 sq./mm. For heavy cables with a cross-section of 16 – 25 sq./mm – up to 500 kg./cm. This parameter is measured by a dynamometer, which is installed between the anchor and the tension loop.


After tensioning the cable, the ends of the cable are grounded, the cable is inserted into distribution devices and connected to protective circuit breakers.

Elements for fastening the cable to the cable

To securely fix the cable with the cable, there are several devices:

The simplest method cable twisting with stretching using ordinary aluminum wireØ 2.5 – 5 mm with insulation. At connections every 50 -80 cm, 7-8 turns of wire are made, tightly turn to turn. To prevent the cable insulation from being pressed through by the fastening wires, the fastening point is wrapped with a rubber plate, and the wire is wound on top. It is recommended to use rubber for gaskets from old car inner tubes;

The device is attached to a guy wire, the cable is laid in a groove, covered with a strap, which is threaded into the lock, tightened and securely fixed. The castle is designed in such a way that reverse side The strap cannot be pulled out; to remove it you can only cut it.

Plates with are produced with loops different sizes. One plate is put on the cable and the other on the cable. In the center of the plates there is a hole with a thread for a bolt; they are aligned and tightened with a bolt.

All connections, regardless of the design, are installed after 50 - 80 cm.

Distribution boxes and lighting devices for cable mounting

To fasten distribution boxes, special galvanized iron plates with cut-out shapes are used. A part of the plate is bent from the cut-out shape, a cable and a box are inserted, after which everything is fixed with bent elements.


To fasten lighting fixtures, galvanized plates of a special shape are used, but the principle of fastening remains the same, shown in the figure.

  • Cable;
  • Plate;
  • Cable;
  • Junction box;
  • Lampshade with lamp socket.

Frequently asked questions for electricians

Question No. 1. You can tighten the cable, then attach the cable and other elements?

It is possible if the installation conditions on site allow this to be done without compromising safety when working at height. But after this you will definitely have to increase the tension, since the load on it will increase.

Question No. 2. What wire should be used to connect the fasteners under the anchor to the ground loop?

Depending on your capabilities, rolled wire with a welded connection or copper, preferably with yellow-green insulation, as determined by the PUE. The cross-section of the wires must be at least 2.5 sq/mm.

Question No. 3. Can I use a cable as a neutral wire?

Yes, provided that it is properly grounded.

Question No. 4. Which circuit breaker install for a cable routed along a cable?

The design of the cable outlet in this case does not matter; the circuit breaker is installed based on the maximum load current in this circuit.

Question No. 5. Can distribution boxes be hung for outdoor wiring?