What to do if hidden cable is damaged

This is not uncommon. With great difficulty, we hang a carpet on the wall, but we are not happy with the result for long: for some reason, the lamp in the room ceases to burn. Or drill a hole in the wallto hang a shelf, but sparks fly out from under the auger, a crack is heard, and the apartment plunges into an ominous darkness and silence.

The cause of the misfortune is simple to disgrace - we are out of luck, and we damaged hidden cable. In the case of the carpet, most likely, a phase or zero core was interrupted. And when they prepared the holes for the shelf, they damaged the insulation of both cores and made a short circuit (the drill can, of course, be thrown away right away).

To resolve the situation, the damage to the line must, of course, be found. In the case of the shelf, this will not be any difficulty - where they fought at the time of the short circuit, there is a damaged area.

With a carpet that we safely hanged, breaking through, that way, with a dozen holes, it will be more difficult. Two questions arise. First: "Which wire is damaged - phase or neutral?". And the second one: “In which of the holes did we damage the cable line?”

If installing the dowel and self-tapping screw in the hole, we interrupted phase wirethen there is a danger of electric shock. A self-tapping screw, a metal profile, metal elements of decor and interior design - all this can be energized if the installation is unsuccessful. You can verify the absence / presence of danger with a working and reliable indicator. In addition, we must remember that the damage can be not one, but two or more. The identified danger should be eliminated by disconnecting the voltage beforehand: unscrew the self-tapping screw, dismantle the metal parts.

Next, you need to determine which part of our apartment wiring is damaged as a result of damage. It is extremely rare that a light disappears in the entire apartment after a line is damaged, usually just one lamp or one or more outlets simply stops working.

If the outlet does not work, then the indicator can check the presence of a "phase" in it. There is a "phase" - the neutral conductor is damaged. There is no “phase" - we are looking for the place of its breakdown with the help of devices that respond to changes in the electromagnetic field, for example, an indicator screwdriver with a phase finder.

It should only be remembered that extraneous cable lines running parallel to the test can interfere and distort the readings. Therefore group circuit breakersthat are not related to our tests must be disabled.

If the lamp refuses to work, then the input cable of the box, the cable of the switch, or the cable of the lamp itself may be damaged. Usually, by the location of the box, you can understand which cable we are dealing with. Damage to the phase conductors of the wiring fixtures are detected when the switch is turned on.

In any case, the breakage points of the phase conductors are usually quite easy.

With a damaged neutral conductor, the situation is a little more complicated. It will be necessary to carry out some preparatory work: turn off the circuit breaker of the affected group, disconnect the damaged neutral wire from the bus and apply a “phase” to it. Further damage can be found in the same way as in the case of damage to the phase conductor.

A similar method detects damage to the lamp switch cable, if they are located after the switch itself. Because the both cores of this cable - phase, then energized in this situation, nothing can be figured out. It will be necessary to turn off the “machine” and the switch, and then apply voltage to the phase core from the lamp side - then you can find the place of the cliff.

At fault finding in neutral conductors it is often unknown which of the wires on the N bus in the switchboard belongs to the damaged line. Then you can disconnect the input neutral conductor from the common bus, open the nearest branch box of the affected group and, having determined the neutral wire, apply the phase to it from the load side. Then everything is as before.

But finding damage is only half the battle. As a matter of fact, this can not be done at all, but immediately replace the damaged cable section. Here a lot depends on the situation. Suppose a damaged wire comes from junction box to a lamp, socket or switch. Then it makes sense to change the cable completely.

But if the band cable coming from housing shieldReplacing the entire cable may seem inappropriate. After all, the cable can pass along the walls of several rooms and have a large length. And in order to replace part of the cable, you will need to install at least one additional branch box, and this is already associated with clearing parts of the strobes. The strob will need to be cleaned to free the ends of the cable passing in the wall, and to prepare the hole for the box.

Strobes clearing - a responsible and requiring caution. It is best done with a hammer and chisel, breaking off small pieces of plaster and trying not to damage the cable. Of course, the voltage must first be disconnected. You should refrain from the power tool, because one careless movement is enough - and the damage will become even more serious.

It is necessary to clear the strob about 15 centimeters from damage on both sides. Then you need to take the ends to the side and hammer drill with crown punch a hole for the junction box. We install the box using alabaster, and put the cable from the stroba into it. If the damage did not particularly reduce the length of the wires, or there is some margin, then you can put a cable on both sides in the box and connect the wires with standard terminal blocks. That is, it is possible to do without replacing the cable by simply connecting the old wires in colors. This is especially convenient if the cable is damaged in only one place.

A new part of the cabling, if any, is usually mounted in plastic box (cable channel). The most important thing here is not to overdo it or damage other cables while drilling holes for dowels. Well, do not forget to disconnect and drown out the old and already unnecessary part of the wiring.

We close the newly mounted branch box with a lid, plaster it, level the wall and glue the wallpaper - the work is completed, you can apply voltage.

Conclusion.

Although it is clear that damage to the cable for hidden wiring is not a “tragedy”, when performing repairs, it is better to pre-use the devices to search for live conductors so as not to create unnecessary problems. Better yet, have a detailed layout of the wiring lines with an accurate indication of the height of the cables. Still, repairing damage is a rather troublesome and dirty business. Yes, and the interior decoration of such a repair will not do any good.

Alexander Molokov

Read also:Schematic and wiring diagrams of lighting in an apartment and a house