"Let there be light" - said the electrician and pressed the switch. Electricity has long become an integral part of modern civilization. And the way it gets into our homes deserves attention.
Electricity is there, but where are the pillars?
Overhead power lines are used as illustrations of the power grids laid in the settlement and beyond its borders. Which for many leads to the illusion that this is the only way. But one has only to ask the question - where are the power lines near high-rise buildings and industrial zones, how do people get into a stupor.
And the answer is simple - they are invisible due to the fact that they are laid underground. And, before moving on to the process itself, a little about regulation: the subtleties describe SNiP 3.05.06-85 (clause 3) and PUE-7 (chapter 2.3, clauses 83 to 101 inclusive). If someone can stand the dry language of official documents, they can get acquainted with them personally. For everyone else, there is this article.
How are electrical cables laid in the ground?
The first stage is trench preparation. It is dug out at the design site of the cable. The trench should not be continuous. Consider the traffic areas of pedestrians and vehicles and do not dig them. This can be done only at the immediate moment of laying the electrical cable (so that later fall asleep and not create long-term inconvenience in movement), which is very clearly seen from the given photos.
In the process, you should remove stones, foreign objects and roots from the soil. The bottom is leveled and rammed. Compliance with one level is not required, the main thing is to avoid sudden changes.
When the place is prepared, the reel with the electric cable is delivered and the laying process begins. It involves the simultaneous execution of several actions.
It:
- checking the integrity of the insulation;
- repair or replacement of the electrical cable (if damage is detected);
- providing protection against negative factors of influence.
Because of this, the process is not moving as fast as it can be (according to a third-party layman who does not understand the intricacies).
These pieces of pipes are called cases. Their task is to ensure the safety of electrical cables in places of increased danger (natural or technogenic unfavorable load). As you can see in the photo above, the project involves laying near a pipe that is already corroded. This creates an increased risk of an accident. We have to decide how to prevent its occurrence even in case of a breakthrough.
Protection against destructive factors is regulated SNiP 3-04.03-85 (depending on the specificity - items from 3 to 9 inclusive).
Corrosion is not the only enemy for the long and reliable service of electrical cables. Equally dangerous is the excessive zeal to do everything pedantic. Do not pull on the cable - it should always be laid in light waves, adding cases in the right places. It is difficult to break it, but it is very easy to create conditions when the service life will be multiply reduced and some other risks appear.
The last stage is burying. Initially, sand is poured, then soil. To warn of danger, a warning tape with a message is placed close to the surface. In addition, the practice of placing bricks on the sand is used to warn the diggers that they are close.
Checking work
When the work is done, you need to make sure that everything works. The electrical parameters are being checked. If there are no complaints, the load is connected. But this is where the work is already being completed.