Do I need to replace wiring ... ?

Hi There,

One of those "I can't believe I just did that moments ...."

I was fitting a kitchen cupboard yesterday, and my wiring detector said that there may or may not be something metal in the cavity where I needed to fix the cupboard bracket. I thought drilling was a bit risky, so I made the holes by hand through the plasterboard, and then pushed my small screwdriver through to see if it was brickwork, piping or something else behind the plasterboard .....

Turns out it was some cabling, because as I was pushing the screwdriver in, all of the electrics in the house tripped out (good old RCD). I was pushing pretty hard - I was convinced it was a wooden baton...

I now know that it was the cable which feeds a double socket, and three fused single sockets (for washer, fridge and central heating).

I turned the electrics back on at the fuse box, and everything is OK now.

My question is whether I can just go on as normal now, or whether there is a fire risk in having some cable that I pushed a screwdriver through, and I need to get an electrician in to check. I'm only hesitating because it will mean having to cut a bit of plasterboard out to make an inspection hole at exactly the point where I need to fix my cupboard to the wall....

With all of the downstairs electrics being on an RCD circuit, do I need to worry - wouldn't it just trip out if there was a problem, rather than melt the insulation on the cable and pose a fire risk ?

What do you guys think ?

To trip the rcd the screw driver MUST have punctured the sheath of either the live or neutral and bridged the earth / cpc core.

You need to chop back plaster / cut out area and physically examine the damage. There's a good chance it's only a scrape and a simple bit of self amalgamating tape will do as a repair.

Chri5 said:

To trip the rcd the screw driver MUST have punctured the sheath of either the live or neutral and bridged the earth / cpc core.

You need to chop back plaster / cut out area and physically examine the damage. There's a good chance it's only a scrape and a simple bit of self amalgamating tape will do as a repair.

Click to expand...

Just to clarify, I assume/hope that Chri5 is advising that the wire be stripped back, the core(s) with damaged insulation repaired with tape, and then the same again over the outer sheath. I still wouldn't recommend that method of repair, though.

Also worth noting that if you don't mind making a little more mess by cutting out two sections of plasterboard, one above and one below the damage, a new section of cable can be crimped in to replace the damaged portion. This will avoid having to remove the board exactly where you want to mount the cupboard.

You could cut a relatively large hole in the wall as it will be hidden by the cupboards anyway, and insert some extra timbers in the studwork to create 'hard points' where you want them for good fixings for the cupboards as well as attending to the damaged cable.

DillonTheCat said:

I now know that it was the cable which feeds a double socket, and three fused single sockets

Click to expand...

A double socket and three FCU's - on one cable! I'd like to think that there's another cable in there somewhere. To find out, open one of those outlets and check for continuity between pairs of matching cores (power off obviously).

I agree with TicklyT. Cut a nice big hole so that you can inspect that cable properly then rebuild the wall with extra noggins exactly where you need them for fixing your cupboard - especially if it's wall mounted.

cut out the plasterboard the whole length of the cupboards, do your repair then replace the removed plasterdoard with 9 or 12mm plywood ( depending on whether you had 9 or 12mm plasterboard )..
you've then got a suitable fixing for all of your cupboards without having to rely on cavity fixings..

Thanks everyone - some really great suggestions, and I'll be getting an electrician to come out and take a look.

Just out of interest, why do I even need to fix it ? If the cable is nicely hidden behind some plasterboard, and everything seems to work OK, why does it actually need inspecting? (honestly - just genuinelyinterested, I will be calling a spark first thing in the morning)

because it now has a hole in the insulation.. sparks like holes... especially if there's somewhere to go nearby, like the earth conductor..

you may also have caused an arc when you tripped the circuit which may have damaged the copper and reduced it's CSA at that point meaning it can't take as much current now..

And if the circuit cables formed part of a RF, and you actually severed a conductor , then the ring would be OC. That would be A Bad Thing.