Cable laying in a trench - basic norms and requirements. Methods for laying a power cable Laying power electrical cables

The power supply of any room or a separate electrical installation begins with an introductory, or power wire. There is no strict definition in the Electrical Installation Rules, the document regulates only the testing and installation of the power cable. In principle, any conductor that connects the supply substation to the input device can be attributed to this type of wiring.

The same category includes wires from the input device to switchboards or cabinets. That is, the cable at the entrance to the entrance machine of your apartment, and the wire connecting the machine to your metering device (electricity meter), refers to the power one. If the meter is installed outside the switchboard, it is also connected to the machines using a power cable.

How to choose the right power cable

Aerial networks that supply power with the help of electric pylons are of no interest to us. The maximum that you will have to face is the power wire from the nearest pole to your private house.

Important! Do not confuse the diameter and cross section of the conductor. The section is the area!

This parameter is not a dogma. For example, the same 4 mm² wire is designed for a continuous load of 38 amperes. With a single-phase connection of 220 volts, this is already more than 8 kW of load. By setting the input protection to 32 amps (with appropriate specifications), you are approaching the maximum possibilities of wiring. It makes sense to use a cross section of the power cable - 6 mm².

The figures considered refer specifically to the power wire. Subscriber wiring to sockets and lighting devices is carried out by residential 1.5 mm². The exception is the power group of sockets for the boiler, electric oven, washing machine. By the way, such wiring can also be attributed to power, but not according to its intended purpose, but according to the load.

A separate topic is color coding. The electrical installation rule prescribes the use of the following colors:

1. Working zero - blue color along the entire length of the conductor.
2. Protective ground - yellow-green insulation, colors are located along the wire.
3. Phase - for a single-phase connection, there are no requirements for color coding.

Let's take a closer look at the third point. With a three-phase connection, each phase has its own color. This is important, because to mix up the phases means to disable the electrical installation. Therefore, the PUE prescribe the following designations:

• A. "yellow" phase
• B. phase "green"
• C. "red color" phase

For a single-phase connection (after a three-phase input), it does not matter which phase and zero form 220 volts.

For reference: the European color marking of phases differs from the requirements of the PUE.

In the vast majority of cases, you will have to install a single-phase power cable. Therefore, the complex marking of three-phase inputs should not confuse you.

Proper power cable routing

If the cable is laid separately from the power plant (switchgear) to the consumer's input, only mechanical requirements need to be met.

Along walls or load-bearing structures, wiring is attached to mounting clips. If the strength of the attachment points is in doubt, you can run the power cable along the guide: a steel band or a carrier cable.

Aerial installation (the cable hangs freely from one anchor point to another) requires either a strong load-bearing sheath or suspension system. The most commonly used steel cable.

If the wire is self-supporting, special tension clamps are used. The cable at the point of approach to the wall or other structure is fixed in the fixture, and its free end is directed to the entry point.

The laying of power cable in trays is widespread. No fixtures are required, the wire fits into the box and closes with a lid. There are only a few restrictions. The joint laying of power and low-current cables is regulated. Rules for the installation of electrical installations. There are no hard prohibitions, with the exception of redundant power lines. They are laid out separately.

The fact is that power cables (if they are not in steel armor connected to protective grounding) form quite strong interference. It is difficult to neutralize them with the help of filters: when the load changes, the nature of the interference also changes. And the power cable is rarely under a stable load.

Therefore, power, signal (communications, computer networks, television), and control lines must be separated. At a minimum, on different sides of the box, and preferably in separate trays.

Regardless of the laying method, the external cable is entered into the room using a curved pipe that prevents moisture from entering the room. The cable must enter it from the bottom up, otherwise moisture can get into the input shield through the sheath.

Splicing Power Wiring

Connecting power cables affects more than just safety. Although a broken live wire will bring enough trouble. A poor-quality splice can cause sparking under load, a progressive increase in resistance, and rapid heating. Despite the non-combustible insulation, this may cause a fire.

In addition, poor contact at the splicing point leads to a loss of cable power, the current strength may decrease.

It would seem, why use pieces of wire if you can stretch an unbreakable chain. However, in reality, breaks happen (it is necessary to make an emergency splice), and the cable may simply not be enough. Therefore, the question: “how to connect the power cable?” worries many.

There are some simple rules:

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External or internal laying of cable lines (CL) is carried out by MasterEnergoService using modern materials, as well as innovative technologies.

The range of services includes:

• coordination of adopted design decisions;
• installation of lines;
• maintenance, repair of equipped lines (if necessary).

It is carried out at objects of varying complexity in the ground in prepared trenches or on specialized structures: tunnels, channels, trays, ducts, cable growths.

In addition, we carry out cable laying on overhead lines with the obligatory consideration of all the normalized requirements of the current standards.

Cabling

We provide services for laying cable lines in Moscow and the Moscow region. In general, this is a responsible job, which should be carried out by high-level specialists in order to ensure the reliability of cable lines. There are many ways to lay cable in the world. In order for you to understand what is at stake, we will talk about the most well-known and reliable methods.

Outdoor cable routing

Outdoor cabling used in cities to hide power lines underground. Cable laying is carried out in trenches, collectors, as well as along the walls of buildings.

Cable laying in the ground

If you want to cable laying in the ground, it is necessary to provide for the presence of a geo-base in the design. Topographic survey will help determine the passage of existing communications, engineering networks and select the most appropriate route for the future cable line.

When designing the laying of cable lines in the ground, the type of soil on the site, the complexity of the terrain, climate features, and the level of groundwater passage are taken into account.

For the underground line, a cable of a special brand is selected - preferably armored, the sheath of which is resistant to chemical and mechanical damage.

The design calculations take into account the construction length and the corresponding number of connecting or branching cable joints of a suitable type.

Laying cables in trenches

If planned laying cables in trenches, then it is desirable to provide line protection.

The cost of these works includes earthmoving and planning activities, as well as the transportation of "extra" soil. The trenches themselves before laying the line can be fixed with special fasteners. The depth of the trenches depends on the features of the cable lines: power, cable brand, type of soil, the presence of intersections with existing engineering networks, communications.

Cable routing depth

If you need to lay the cable in the ground, pay attention to the depth of the installation. Remember, whether you're using trenches, conduits, or cable trays, you need to take it seriously. Cable routing depth should be at least 0.7 m. Also, in any case, do not place an unprotected cable in water, it is better to place it in a HDPE pipe.

Intersection with deep-laying communications

Before starting work on laying the cable, it is necessary to familiarize yourself with the geo-base in order to correctly position all communications. We must remember that everything intersection with deep-laying communications are regulated in order to withstand the security zones, as well as to create the necessary conditions for repairs. In addition, when laying in parallel, the cables must be spaced 10 cm apart.

Internal cable routing

One of the most popular methods is internal cable routing, it involves the installation of materials inside the building. This method differs significantly from the external gasket, both in terms of execution mechanics and cost. First of all, there are many strict rules that must be followed when laying inside. For example, you must remember that the shell of all materials must have a fireproof layer.

Cable Laying Techniques

As we said at the beginning of our material, there are many methods and methods for laying cables. Recall, for example, hidden cable installation, which is mainly used indoors. For this type of gasket, wall chasing is used - recesses in which the cable is hidden. The advantages of this method, of course, include the aesthetic appearance and safety, the protection of the cable from external damage. Also, you can run the cable in a conduit or tray, which is very common in many office buildings. This is one of the fastest and most economical ways, which is convenient in further operation.

If you need to lay a cable or need advice, MasterEnergoService professionals are ready to help you resolve all issues. Here you will find responsible and executive specialists, whose experience can only surprise you. Contact us right now!

Laying (installation) of power cable

The power cable is an indispensable element that is always present in the process of electrical installation. Therefore, every professional electrician knows how to lay (install) a power cable. The whole process, like others, is preceded by the development and approval of the project, which determines the type, cross-section of the cable, and the method of its laying.

There are several types and methods of laying (installation) of a power cable. Among them are cable laying in trenches, open and hidden laying inside buildings and structures, outdoor cable routing along the walls of buildings.

Underground laying of a power cable implies manual or mechanized installation, using a cable layer, at a given depth. When using this method, pay attention to protecting the cable from various mechanical damage.

Open and hidden cable installation is carried out inside buildings. Open means laying the cable over walls and ceilings, hidden - laying inside the walls, foundation, floor, in cable channels.

Outdoor installation is the laying of a power cable along the outer walls of buildings or on supports. This type of installation is further divided into open and hidden.

Repair of cable lines

Run repair of cable lines of varying complexity will help the specialists of the company "MasterEnergoService". According to your application and the examinations carried out, we will carry out all the necessary measures, including:

• measurements of CL before the start of repair work and after their completion;
• change of damaged sections of a cable line passing openly (along trays, cable lines, overhead lines) or closed (in blocks, boxes, pipes, trenches, tunnels);
• change of connecting or branching couplings;
• cleaning, repair of cable channels, structures;
• relocation of CL sections.

In addition, at MasterEnergoService you can order the repair of such structures: cable ducts, cable wells and pits, cable glands.

Tell us what you need to do, and we will answer how much it costs!

The cost of laying a cable in Moscow and the Moscow region depends on the type of installation, the amount of work and the complexity of the task. Electricians-MSK offers a full range of services for laying power cables and wiring. The use of modern technologies and equipment, as well as the high qualifications of our employees, allow us to set an acceptable cost for cable laying and guarantee the impeccable quality of the tasks.

The cost of laying a power cable and types of work

The cost of installing power cables directly depends on the chosen laying method. Employees of the Electricians-MSK company, having access groups for all types of work, perform:

• External cable routing, the cost of which is significantly lower compared to the price of flush-mounted installation. In this case, the wire is fastened with staples and staples.
• Concealed installation. Cable laying, the price of which is indicated in our price list, involves chasing walls and laying cables in hot-smoked partitions. The wire will be hidden from prying eyes, inaccessible to children and pets.
• Laying the cable in the cable channel. The best option for an office, a shopping center, a summer house: the cable is placed in a special box, and the owner of the premises can easily add an additional wire to the cable channel or repair the wiring.
• Trench installation of a power cable (a specific method of underground laying of a power wire is described in the project).
• Installation of overhead lines using porcelain insulators and stretch marks.
• Laying of low-voltage cables (telephone, TV, alarm wires, etc.).

Price list for cable installation:

Installation of electrical cables is carried out in strict accordance with the requirements of the Rules for the installation of electrical installations by qualified specialists. All work has a lifetime warranty. If necessary, our employees will assist in the process of drawing up project documentation and obtaining the necessary permits, as well as help to purchase all the necessary equipment and consumables.

Alsera performs all types of work related to the laying of power cables:

• laying power cable in trenches (including punctures under roads)
• laying of power cable on cable racks, in cable ducts
• installation of power on the facades of buildings and structures
• arrangement of overhead cable lines

Having vast experience in this field and having our own material and technical base, we guarantee the Customer high-quality performance of work within the time frame clearly indicated by the Contract. The work is carried out by qualified specialists under the constant supervision of the responsible foreman of the site. Our employees have all the permissions and permits necessary to carry out the work.

We carry out a comprehensive supply of cable and wire products and all materials necessary for the production of work. Own transport department will ensure prompt delivery of materials to the site.

When contacting our company, we guarantee the prompt solution of the tasks, starting with the preparation of estimates and ending with a laboratory report. To draw up a commercial offer for the professional installation of a power cable, you can send the terms of reference, project, or diagrams to us by mail [email protected], or call an engineer to the facility.

Departure of our engineer to the object (within the Moscow Ring Road) - free of charge!

The cost of laying the power cable

Photos of works:

Contact us at the phone number listed in the "Contacts" section, and you will receive a durable and reliable power cable that will provide you with uninterrupted power transmission to any point!