If earlier power wires, including high-voltage cable lines, as well as telephone lines were mounted at a height, to poles, then in recent decades they have been laid underground. So, the airspace above settlements was cleared, the wires were protected from the negative effects of the environment, their safety and integrity no longer depended on the rampant elements or the invasion of bird flocks. The underground method of laying proved to be technically and economically more profitable and productive.
Earth installation work
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 select must meet the required standards for insulation and protection, resistance and power.
Laying the cable in the ground requires compliance with some rules:
- It is better to choose an armored cable, respectively, of the VBBSHV or VBBSHVNG brands. Their advantage is that they are enclosed in a steel protective tape, which reliably saves them from damage of a mechanical nature, 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. Such work is preferably carried out on a terrain cleared of foreign objects (or so that the distance from the place of laying to the nearest trees is not less than a meter). In addition, the wires should not lie under the terrain where heavy loads are noticed: car parking spots, buildings under construction, etc.
- Cable laying in the ground, if it is being carried out near residential or other buildings, must be at least 60 centimeters distant from objects. Laying the cable under the foundation is strictly prohibited. Your communications must not overlap with other existing communications lines and utilities. They are best done in parallel or remotely from each other.
- Having outlined the main paths where the cable will be laid, the trench should be dug out according to the scheme. So, laying a telephone cable can be done at a depth of 80 centimeters to one meter in a free area. If communications should be laid in places of increased soil exploitation, the depth of the trench should be at least 1, 25 / one and a half meters;
- All soil must be cleaned of earth and construction debris - stones, branches, etc., so that they do not interfere with work and do not threaten damage to the wires.
- In the dug trench you need to make a "pillow": pour a layer of sand at the bottom of 12-14 centimeters. It must necessarily cover the bottom evenly and be the desired thickness.
- The laying of the power cable, more precisely, the choice of its type, depends on the power of the mains, which 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. For this, it is placed in special protective "cases-covers" from pipes of the PND brand.
- Next, the cable is laid in the ground along the trench, without tension. It is especially important that slack and allowance be present in wavy lines. Protective cases are stacked in advance. To ensure a high-quality power supply or a telephone line signal, the cable should 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 detect.
- Having finished laying, the cable is again covered with sand - the upper "pillow", the thickness of which is from 10 centimeters.
- The "pillow" is filled with soil and rammed. A layer of earth - from 17-20 centimeters.
- On top of the entire length of the conduit, a signal tape is laid, then the trench is finally filled up, rammed, the ground is leveled.
- The last step in laying the cable in the ground is to re-measure the resistance, check for the presence / absence of a short circuit, and ground the armor.
When the main excavation works are completed, everything is checked, you can start wiring the cables inside the building and connect the corresponding devices to the electric or telephone network.