Installation of wiring in a cable channel: common mistakes and misconceptions

  • Dec 14, 2020
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The advantages of laying power and signal lines in cable ducts include ease of installation and cost-effectiveness. This can be done independently by a person who is not familiar with the technique of arranging electrical wiring. But when working, it is important to comply with the requirements of current regulations. (GOST 50571.15-97, in particular) and try to avoid common mistakes.

When plastic channels are used

Plastic or steel cable ducts are used in cases when it is not possible to hide the wiring in the walls for some reason. This option is also used when laying it down when you need to build up an existing line to install a new outlet, for example. In addition, the cable duct can be used in private houses with timber or log walls.

According to regulatory requirements (see PUE 7 clause 1.1.13 and table. 2.1.2-3.) in bath buildings, shower rooms and similar "damp" rooms, the wiring of power lines is allowed only in cable trays. This can be clearly seen in the photo below.

Typical installation errors

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Common mistakes made when installing a cable duct include:

  • the route of the laying was selected incorrectly;
  • the rules for cutting and fastening workpieces were violated;
  • the wires are too tightly laid within the box (the dimensions are incorrectly selected);
  • power and low-current lines are laid close to each other.

In the first case, if the wiring arrangement is incorrectly selected, it may be destroyed due to mechanical damage, for example. In addition, it should not be located close to heating and gas pipes. (see SNiP 3.05.06-85 p. 6.4. 2.).

It is necessary to cut the blanks of cable trays of the required length using a hacksaw for metal or special scissors designed specifically for this purpose. The latter are presented in the photo below.

It is undesirable to simply "bite" the edges of the plastic with side cutters, and then break it. This approach often leads to damage to the plastic channels and deterioration of their protective properties.

It is recommended to use special glue for fixing only if you are sure that you will not change the selected route of the gasket. Otherwise, it would be more correct to use ordinary self-tapping screws of a suitable standard size.

Note: It is a mistake to wrap them directly into the base of the plastic box, which leads to the appearance of cracks in it (as in the photo below).

You can avoid these troubles if you drill holes in the attachment points in advance, the size of which is slightly larger than the diameter of the screws.

Another common wiring error is the wrong width of cable channels. In this case, the requirements for cooling the wires are violated, which turn out to be laid very tightly. A margin of width will not hurt even in the event that over time it is necessary to increase the number of wires.

And, finally, the joint placement of power and signal conductors can lead to disruptions in the operation of the equipment controlled by them.

Professionals advise to choose plastic products with multiple channels (with a longitudinal baffle) and use them separately.