Laying a cable line: methods, rules for installing electrical lines

Power supply networks and their arrangement include a wide range of different activities. Among them, the laying of cable lines plays a huge role. The process of their installation is carried out using special methods and technologies. In addition, all work can only be carried out by specially trained and authorized working personnel. Depending on the purpose and territory where the cable will pass, its installation is carried out in order to ensure maximum protection during operation.

Line installation methods

There are a lot of ways to lay cable lines, and they are mainly used in industrial enterprises operating with different voltage values. Cables can be run both indoors and in the adjacent territory. Indoor installation is carried out by the following methods:

1. Cables are laid along walls, industrial structures and building structures.
2. They are pulled through pipes, which are laid in an open or hidden way.
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3. Special boxes, trays and cable channels are used for installation.
4. The cables are tied to pre-tensioned cables.
5. Electric lines are carried out in special structures, which are double floors, cable shafts, floors, etc.

To prevent electrical wires located inside structures and premises from being damaged, installers carry out a number of protective measures. For this, the cables are treated with fire-resistant backfill or solidifying liquid mass. In places where the electric line passes from one room to another, blocks are installed to protect against fire.

Structures for cables

For the installation of lines on the territory of enterprises, standard structures are mainly used. These include tunnels, overpasses, trenches and other structures. Tunnels allow you to save a lot of territory, carry out the laying of new lines and easily maintain the laid cables.

Their only drawback is the high cost of building such structures. To save money on the installation of lines, they are pulled along special overpasses and galleries. This is especially true if there is a large number of cables running in the same direction. So, overpasses are built when installing from 20 to 30 lines, and when there are 50-60 lines, galleries are used.

Structures are placed on load-bearing columns and beams with a height commensurate with the roads and structures to be crossed. For example, when crossing a carriageway, it must be at least 4.5 m. In addition to electrical lines, pipelines are jointly installed on such structures for various purposes.

Galleries and overpasses are necessarily equipped with ladders and platforms for carrying out maintenance work. If it is necessary to lay from 1 to 6 cables in one direction, usually dig a trench in the ground. In this case, the installation is carried out without additional structures, but always with a pillow and a protective layer of sand.

Electrical line laying rules

All processes associated with the laying of electrical lines during construction and installation work are the most critical stage. The choice of the type and method of cable installation is carried out in accordance with the "Electrical Installation Rules". The brand of the electric wire is determined based on the transmitted power and the design features of the line specified by the project.

At the same time, the main requirement for choosing the right brand is to maintain insulation during the operation of electrical wires. For example, when connecting mobile mechanisms, only flexible cables are used, which must maintain insulation after repeated bending.

If the line is laid in a long section with different soil characteristics and unequal environmental conditions, then the choice of the type of wire is carried out according to the analysis of the most difficult place. The rules define the special conditions for laying cables:

1. When laying underwater electrical lines, wires with round wire armor are used. Usually these are single-core specimens that do not have PVC insulation.
2. Armored cables are used in places where ground displacement can occur and on overhead lines.
3. The use of wires with aluminum conductors in explosive production and metallurgical enterprises is not allowed.

The rules also define the number of couplings per kilometer of the line. Depending on the voltage in the line, their number ranges from 2 to 6 pieces.

High voltage wires in the trench

The most popular and widespread method of laying electrical lines is trench method. It is considered the most reliable and safest during operation, and with the help of a trench, you can lay a line in the shortest possible time. First, the direction of the track is determined and its axis is marked with pegs.

Then a trench is dug using a technique or manually. The width of the ditch is determined by the number of cables and the depth is determined by the size of the voltage. So, when laying a cable for 10-20 kV, the depth will be 1-1.2 m. Under special conditions, the depth can be reduced to 0.5 m. For example, when a trench crosses other communications.

In rural areas, the depth should be at least 1 m so that the cable does not interfere with agricultural work. A sand cushion with a thickness of at least 0.3 m is poured at the bottom of the trench, while all debris and stones must be removed. Then the cable is laid and a protective layer of sand is poured on top.

When crossing the roadway, the wire is pulled through a piece of metal pipe. On the protective layer of sand, be sure to lay out a signal tape, warning of the presence of a cable. After completing all the work, the electric line is covered with soil.

The relevant services will display warning signs prohibiting excavation in this area. And also the highway is tied to existing buildings or fixed objects and entered into the communications scheme.