If earlier power transmission wires, including cables of high-voltage lines, as well as telephone lines, were mounted at a height, to poles, then in recent decades they have been laid underground. Thus, the air space above the settlements was cleared, the wires were protected from the negative effects of the environment, their safety and integrity no longer depended on the wild elements or the invasions of bird flocks. The underground laying method turned out to be technically and economically more profitable and productive.
Earth and installation works
When planning to lay a power or telephone cable underground, you must remember that not all wires are suitable for this type of operation. The cables you choose must meet the required standards for insulation and protection, resistance and power.
Laying a cable in the ground requires following some rules:
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cable laying in the ground It is better to choose an armored cable, respectively, of the brand "VBbSHV" or "VBbSHVng". Their advantage lies in the fact that they are enclosed in a steel protective tape, which reliably preserves them from mechanical damage, from earthen rodents and exposure to moisture from groundwater.
- Cable laying in the ground should be carried out in areas that are not clogged with large tree roots. It is desirable to carry out such work on an area cleared of foreign objects (or so that the distance from the installation site to the nearest trees is at least a meter). In addition, wires should not be laid under terrain where heavy loads are seen: car parking lots, buildings under construction, etc.
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power cable laying Cable laying in the ground, if it is carried out near residential or other buildings, must be at least 60 centimeters away from objects. Laying the cable under the foundation is strictly prohibited. It is impossible for your communications to intersect with other existing communication lines and engineering grids. It is better to carry them out in parallel or far from each other.
- Having outlined the main paths where the cable should lie, according to the scheme, you should dig a trench. Thus, the laying of a telephone cable can be done at a depth of 80 centimeters to one meter in a free area. If communications must be laid in places of increased exploitation of the soil, the depth of the trench should be at least 1.25 / one and a half meters;
- All soil must be cleared of earthen and construction debris– stones, branches, etc., so that they do not interfere with work and do not threaten damage to the wires.
- In the excavated trench, you need to make a “pillow”: pour a layer of sand 12-14 centimeters into the bottom. It must cover the bottom evenly and be the right thickness.
- Laying a power cable, or rather, the choice of its type, depends on the capacity of the power grid that is supposed to be installed, on the needs of consumers in energy. All settlement work is carried out in advance. When the right amount of wire is purchased, if it runs under areas with increased load, it should be further protected. To do this, it is placed in special protective "cases" made of HDPE pipes.
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telephone cable laying Further, the laying of the cable in the ground is carried out along the trench, without stretching. It is especially important that the slack and allowance be present in the wavy lines. Protective cases are stacked in advance. To ensure a good power supply or telephone line signal, the cable must be solid, not lumpy.
- When laying more than one cable in one trench, each of them must be separated from the other by at least 10 centimeters.
- Those places where the cable will come to the surface must be marked so that they are easy to find.
- After finishing the laying, the cable is again covered with sand - the upper "cushion", the thickness of which is from 10 centimeters.
- "Pillow" is covered with soil and rammed. The layer of the earth is from 17-20 centimeters.
- A signal tape is laid on top of the entire length of the conduit, thenthe trench is finally filled up, rammed, the earth is leveled.
- The last step of laying the cable in the ground is re-measuring the resistance, checking for the presence / absence of a short circuit and grounding the armor.
When the main earthworks are completed, everything is checked, you can start wiring the cables inside the building and connecting the relevant devices to the electrical or telephone network.
