Damaged a meter neutral feed cable to CU

bobdabuilda · 12 Mar 2011

I am currently renovating the downstairs cloakroom. After removing the sink the drylined wall was a mess so I cut back the loose plasterboard but in doing so I have nicked the neutral wire of the electrical supply from the meter box to the internal consumer unit.

The meter box is externally just to the right of where those cables are coming in at a diagonal angle and the consumer unit is mounted up near the ceiling on the far left as you look at the picture.

Picture Title

bobdabuilda
12 Mar 2011
1

The wall to which the cables are fixed is a thermal block and really should have been chased out and the cable inlaid before trunking over with steel conduit, but as you can see the electricians at bryant just surface laid them and didn't bother with the protective steel conduit over the whole length! Suffice to say this wouldn't have happened if they had done it properly especially seeing as that is where the toilet roll holder should be mounted and the previous owners narrowly missed screwing into the live feed!

Untitled

bobdabuilda
12 Mar 2011
1

Untitled

bobdabuilda
12 Mar 2011
1

Picture Title

bobdabuilda
12 Mar 2011
1

Untitled

bobdabuilda
13 Mar 2011
1

Picture Title

bobdabuilda
13 Mar 2011
1

Picture Title

bobdabuilda
13 Mar 2011
1

Untitled

bobdabuilda
13 Mar 2011
1

My question is whether I can just patch the nicked neutral cable with some hotmelt glue or insulation tape or does the whole thing need to be taken out and rewired?

ricicle · 12 Mar 2011

You are lucky you didn't damage the Line conductor if you were using a metal knife/bolster chisel.
Has the copper been exposed/damaged. Repair may be possible in situ. with tape but you would need to be absolutely sure that the cable is intact.
If the copper is damaged then you need a competant electrician to replace or possibly mechanically crimp the cable.

Incidentally is this a fairly new build - I would be chasing the install company about breaches of BS7671 !

I would also not be happy about leaving that as it is either.

bobdabuilda · 12 Mar 2011

Thanks. The property was built by Bryant in 1996 and according to Taylor-Wimpey ,who now own the company, they only keep records of the build for 6 years.

The copper core is definitely intact and it is only the outer sheath that has been skimmed off by the plaster knife. (click on the pics for enlargement) Thank fook that it wasn't the live or I wouldn't be typing this now and would have missed the rugby today!

fireman22 · 12 Mar 2011

just wrap some insulation tape around it then, if you have a double pole switch near the meter before the cables come into the house switch this off, just in case they have used neutral coloured tail as the live

bobdabuilda · 12 Mar 2011

I have checked that it isn't live and it isn't.

fireman22 · 12 Mar 2011

make sure the neon screwdriver is working tho,

you can just wrap tape around it.

bernardgreen · 12 Mar 2011

fireman22 said:
make sure the neon screwdriver is working tho, you can just wrap tape around it.

Yes wrap tape round it and throw it in the bin. They can give dangerous false readings.

Wrapping tape around that damage cable is NOT the ideal repair.

There is a more serious concern. There are cables which have a 60 amp or 100 amp SLOW blow fuse ( the company fuse ) as their only protection.

They should NOT be hidden behind plaster without a clear indication of the serious danger to anyone fitting things to that wall. I am not so sure they should be hidden at all. They are close enough that one screw of a metal fitting could go into the neutral which would not be noticed and the second screw goes through the live. 60 amps through a toilet roll holder would be spectacular and extremely dangerous.

Monkeh · 12 Mar 2011

bernardgreen said:
60 amps through a toilet roll holder would be spectacular.

Don't go giving people ideas!

bobdabuilda · 12 Mar 2011

I'm not entirely stupid so I tested the neon screwdriver on the live of the c.u first and it works fine....
It would certainly be one Hell of an enema for the unfortunate soul! I just wish I could get the sparky who wired it that way to test it!

Now I know that it's there and done so badly I can't really leave it like that especially as it could kill some future owner... so it looks like I'm going to have to get someone in to do it properly after ripping off the rest of the plasterboards. So much for a little diy job, my wife owes me some serious bj vouchers for this.....

Any ideas of the rough cost for such a job if I just get the wiring done and do the other work myself?

bernardgreen · 12 Mar 2011

bobdabuilda said:
I'm not entirely stupid so I tested the neon screwdriver on the live of the c.u first and it works fine!

I didn't say you were stupid.

The neon lights if there is enough capacitive coupling between the person holding it and ground to provide a path for the current required to light the neon to flow from live wire to ground.

If the person's capacitive coupling to ground is too small the neon cannot light.

If the person is close to a live wire such in a switch cable and is more "live" than "earth" then current to light the neon can flow the other way. From live capacitively to the person and through the neon to a neutral or earth on the wire they are testing.

bobdabuilda · 12 Mar 2011

bernardgreen said:
I didn't say you were stupid.

I know you didn't, I was answering fireman22 re making sure it was working, so relax and thanks for the info! (I will use a multimeter in future)

fireman22 · 12 Mar 2011

bobdabuilda";p="1928589 said:
I'm not entirely stupid so I tested the neon screwdriver on the live of the c.u first and it works fine!

i didnt say you were stupid either, i know neons can fail or not light up in the right / wrong conditions, i was just thinking of your safety, no need for the ! either

bobdabuilda · 12 Mar 2011

I apologise if you feel aggrieved!!!!

sparkydude · 12 Mar 2011

And thats why you are not competant to be thinking about anything to do with electrics. Most silicone sealants exude acetic acid (vinegar ) whilst curing, thus damaging the copper conductor. The only way to repair this cable would be to use a form of self amalgamating tape such as the link below

http://www.alfatape.co.uk/

Please do not suggest stupid ideas to repair things such as this as there is always some idiot who will try it and then end uo killing themselves .

Those cables are not in the prescribed zones and so should be moved to comply witht he regulations. Is their not a sticker on the DB with the installers name and address??? if so go to the trade body they are registered with and lodge a complaint.

Nick

AdrianUK · 12 Mar 2011

AndyPRK said:
if it were me I would put a some white silicon sealant over it. (like bath sealant)

Is silicon sealant insulating until its totally dry????

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Damaged a meter neutral feed cable to CU

Similar threads