Cable Insulation Repair After Accidental Screw Damage in Three-Phase Wiring - Safe to Plaster?

Hello

I know that the problem of a damaged cable in the wall has already been described, but in my case the damage was unusual, because when I tried to screw the screw into plaster and not while drilling. The screw did not damage the wires noticeably, only the insulation.

The screw was hammered into the cable of the three-phase wiring. I forged the cable about 40 cm long and removed the white cable cover for a few cm. The insulation on the N and PE wires was punctured, the wires were not damaged apart from minor scratches.

I separated the wires and insulated the damages with insulating tape over 1mm thick. Then I washed the cable a few cm on both sides of the damage and wrapped the whole thing with several layers of tape, overlapping 3-4 cm on each side over the undamaged cover.

My question: can a cable insulated in this way be plastered again or should I make a hole next to it, cut the cable and connect it again in the box?

I would like to add that there is no difference in the three-phase installation in the apartment, so in the event of a significant leakage, nothing will indicate a problem.

I am committed to a safe and permanent solution.

moriel wrote:

I am committed to a safe and durable solution.

The surest way is to replace the entire cable. But possibly you can insert a can in the place of damage and connect in a can. I had a similar situation during the renovation, I put a screw in when I screwed the plasterboards to the ceiling into the lighting cable. I decided to replace the entire cable. It is the safest and most sure that.

moriel wrote:

I separated the wires and insulated the damages with insulating tape over 1mm thick. Then I washed the cable a few cm on both sides of the damage and wrapped the whole thing with several layers of tape, overlapping 3-4 cm on each side over the undamaged cover.

Essential question. Why do you ask for help "after" the repair is done and not "before"? Do you want praise? Well, she won't be there!
It has been written many times that insulating tape is not a permanent but a "temporary" protection. Because many times during work, it is convenient to insulate the wire with tape. However, this protection changes its parameters over time, so it cannot be left indefinitely.

On the other hand, repair kits are used to secure wires, cables and their connections.

I have not plastered the damaged area, so I do not think that it is "after" the repair. I don't have internet access at the construction site, so I couldn't ask sooner.
I secured as much as I could and now I am asking for an opinion and suggestions.

By repair kit I mean heat shrinkable sleeves?

If there is a problem with replacing this cable or it is a very long section and the cores are not damaged and the insulation is "cracked", I would insulate it with self-vulcanizing tape. Unfortunately, such a tape (good) costs a little: PLN 30-50. I do not recommend just any.

You did it correctly, fill this wire and sleep well :)

Moderated By retrofood:

I am giving this outstanding insight a prize.

stonefree wrote:

You did it correctly, fill this wire and sleep well

Hello. Of course, do not be surprised then that the RCD will blast out.

Maybe pay attention that only the N cable was damaged because PN and so it is available everywhere for the user, e.g. device housing.

There should be PE

Is it some new creation, this PN? Where was he born?

qadam12 wrote:

Hello. Of course, do not be surprised then that the RCD will blast out.

Maybe a colleague will explain why he scares by firing an RCD?
Of course, he should use a self-vulcanizing tape and only put a regular PVC tape on top of it.
I recommend one more approach to the subject and the use of self-vulcanizing tape.
I also believe that:

stonefree wrote:

The greatest folly would be to rip the wall and replace the entire cable, and even more so, to cut undamaged wires and connect them with a terminal strip.

Stonefree, just like I, was censored and ended up in the trash. We had a different opinion than the "only correct" one, we think that my colleagues are over-exaggerating with this replacement of the cable or cutting the veins just to put on a heat shrink.

Hello

In the event of such damage - the electrician's task is to assess the damage and take appropriate action. In a situation where the veins are practically not damaged, they retain their cross-section at the point of damage (i.e. they are only scratched) - repair is limited to repairing the insulation.

Then cutting the wire and using a repair kit (a set of heat shrink tubes and cable crimp ferrules) is here like shooting a cannon at a sparrow. Even better are ideas with a can (probably much needed at this point ).

So as you can see I agree with freemasons, stomat and stonefree.

On the other hand, the method of repairing the insulation of the conductor is interesting - both for the individual conductors and for the outer sheath. (YDY cable). It is obvious that the insulation must be done correctly - not inferior to the electrical insulation of the cable itself, mechanically strong and does not change its properties over time.

This is where questions arise - is insulation with the popular insulating tape incompatible with the art? Some colleagues suggest using a self-amalgamating tape - is this solution ok? An interesting idea was suggested by the freemasons - to use both in the right order. What about the insulation of the veins - are there any suggestions?

kisses
- GIFT-

Of course, self-vulcanizing insulation should also be wound on the veins, then PVC insulation, that is, rebuilding the insulation of the veins. Rebuilding the external insulation (cable sheath) is the same, first self-amalgamating insulation, then PVC surface insulation.
To be fully happy, the tape wound insulation should be at least 1.5 times thicker than the factory insulation. This is how I was taught at school and this is also the conversion factor used in MV cable joints (at least a few years ago it was the case).
The rebuilt insulation always has worse properties than the original one, therefore it must be thicker. Self amalgamating tape should never be used, it should always be covered with PVC tape.
I have never agreed and still do not agree with the statement that electrical tape is only a temporary measure (there was a topic about it once, anyway).
some of my colleagues try to find the problem where it is not.
It is heresy to cut healthy veins just to put them on.

Hello

I have to confess to my fellow Mason that I agree with you on the comma
You have correctly presented the method of insulating the repaired cable.
The PVC tape is needed externally, for example as a barrier to chemical factors that may occur at the joint (calcium compound in the plaster). In turn, self-amalgamating tapes seal the connection better (moisture). There are two more chemical interactions - the reaction with the PVC of the wire insulation, and the reaction with the contact with copper (depolymerization and the reaction of chlorine with copper). I will not discuss these things as electricians are not chemists, and you can find relevant information in the information sheet.

The belief that insulating tapes are "temporary protection" may stem from experience with low-quality electrical insulating tapes. This poor quality is usually due to bad glue. Once someone bought me a tape that detached itself - and right after sticking it, the glue dries quickly. Another time I had tape the glue of which became very fluid over time.

In my opinion, in internal conditions (where there is no high humidity) - good PVC electrical insulating tapes can be used as a durable and the only insulation. I often use regular HelaTape Flex 15 and I have no objections to it. If there is such a need, you can use HelaTape Flex 20 - after gluing it is equal to the mechanical and electrical strength of "heat shrinks". There is a whole range of PVC tapes with even better parameters for which you have to pay an increased price.


kisses
- GIFT-