Have a major problem

[james stas]

Hi guys, i'm not an electrician ,I'm a builder.

a month ago we had an electrician in first fixing, after he left some capping fell off and i put it back on with a nail. turns out i nicked the cable but it wasnt live until yesterday when he second fixed the outside light and powered on and left. I wasnt on site but later the customers got a shock from the wall several feet from the cable, the whole wall was live , because it was damp from the plastering i had done (like 3 weeks ago) and i nicked the cable. so its all my fault i am told.

Should this not have been picked up on the insulation resistance test?
And why did the electrics not trip? i mean if i put the nail into the cable today would it trip or would the whole wall be live? i got a severe telling off for putting customers lives at risk but builders sometimes damage hidden cables and it always trips and never in my life have i heard of a whole wall being live like this was.

Please post honest opinions. i need to know if its my fault.

thanks
James

 

[james stas]

forgot to add he just changed the fuseboard also

 

[Pete999]

Hi guys, i'm not an electrician ,I'm a builder.

a month ago we had an electrician in first fixing, after he left some capping fell off and i put it back on with a nail. turns out i nicked the cable but it wasnt live until yesterday when he second fixed the outside light and powered on and left. I wasnt on site but later the customers got a shock from the wall several feet from the cable, the whole wall was live , because it was damp from the plastering i had done (like 3 weeks ago) and i nicked the cable. so its all my fault i am told.

Should this not have been picked up on the insulation resistance test?
And why did the electrics not trip? i mean if i put the nail into the cable today would it trip or would the whole wall be live? i got a severe telling off for putting customers lives at risk but builders sometimes damage hidden cables and it always trips and never in my life have i heard of a whole wall being live like this was.

Please post honest opinions. i need to know if its my fault.

thanks
James

This Electrician that did the first fix, was he the same Electrician who di the 2nd fix and testing and eventually livening up the installation?

 

[james stas]

yes he was the same one

 

[james stas]

how can you test a cable with a nail though it an it passes? and doesnt even trip out the electrics but shocks people 6 feet away through plaster ?

 

[Dave OCD]

He couldn't have been up to much if the capping just fell off the wall. Sounds as though he didn't do the required testing to me as well.

 

[Pete999]

yes he was the same one

Any testing carried out by this bloke? I would suggest he is the one responsible, your repair was the cause, but he should have picked it up during the testing procedure, that is if he did any testing

 

[Dave OCD]

If the problem only shows with the light in question switched on the fault is between the switched live and earth and if said switch was off [which it shouldn't have been] when he tested it wouldn't have shown up. But regardless it should operate the RCD - unless the nail has severed the CPC and there's no continuity on it back to the CU.

 

[westward10]

No guarantee any testing would have highlighted it unless there was a path to earth from the damp plaster say through an earthed metal back box.

 

[Pete999]

Was an Electrical Installation certificate EIC issued

 

[NellyManjaro]

In my opinion is a bit of both... you shouldn't of touched it... wasn't your job to do it...

BUT that being said... if I'm not mistaken... if the wall was live that means that under an IR test surely there would of been a very low reading between earth and live... if the current can travel that far through the wall then it can reach the socket/switch iits supplying which will be earthed.... this will be earthed to the wall that is effectively live UNLESS it is not properly earthed.

I can only assume if the wall is still damp after 3 weeks then it is not a stud wall you went old-school and bonded/rendered

Very difficult one this... i could be wrong but from what you have said i think thats right... but never had or heard of this before so good luck!!!

Let us know the outcome

 

[Pete999]

No guarantee any testing would have highlighted it unless there was a path to earth from the damp plaster say through an earthed metal back box.

An IR test should have picked something up.

 

[james stas]

Thanks for all the replies guys. I have asked for a copy of the test. awaiting a response. Iput the nail in on the edge of the capping so it would have only been nicked not severed, What is CPC?

The capping was sitting proud of the plasterline because existing bad brickwork on the wall pushed it out from half the height, so i put a nail in on the edge of the capping near the top to hold it in. i couldnt board it so i bonded it with backing plaster then skimmed the whole wall as usual.

 

[Pete999]

Thanks for all the replies guys. I have asked for a copy of the test. awaiting a response. Iput the nail in on the edge of the capping so it would have only been nicked not severed, What is CPC?

The capping was sitting proud of the plasterline because existing bad brickwork on the wall pushed it out from half the height, so i put a nail in on the edge of the capping near the top to hold it in. i couldnt board it so i bonded it with backing plaster then skimmed the whole wall as usual.

CPC Circuit Protective Conductor (Earth Wire)

 

[Des 56]

A woman was killed when a partition wall was made live by a screw,there was a water leak in that location which conducted it enough that when she bridged herself between this water and a earth source she got electrocuted

I tell you that because the wall may very well have been made live by a nicked cable,testing however may not show anything if the resistance of the wall to the earth source under testing is too high
The person touching the wall along with a better earth source may very well pick up this fault better than a insulation resistance instrument
Even the space shuttle was not immune adequacy of testing during certain circumstances,its unlikely for there to have been be a severe electric shock from that situation

 

[Strima]

If the nail had just nicked the line conductor an IR test may not have shown a fault to earth as the wall may not have had a good path to earth, only when touched it would have completed the path to earth.

 

[Leesparkykent]

The RCD should of tripped though as there would be an imbalance between line an neutral...As westward10 says there is no guarantee an IR test would pick it up although you would of thought the metal back box that's earthed and in contact with the damp plaster would pretty much guarantee an unacceptable IR reading. Something isn't right IMO.

 

[westward10]

An IR test should have picked something up.

Why we can't see or know the full circumstances. The incident Des refers to is a classic example where the electricians were blamed for inadequate testing and whilst this may be correct the chances of correct testing identifying the fault is remote to say the least.

 

[Leesparkykent]

Why we can't see or know the full circumstances. The incident Des refers to is a classic example where the electricians were blamed for inadequate testing and whilst this may be correct the chances of correct testing identifying the fault is remote to say the least.

I believe with the Emma Shaw tragedy though it was concluded that the mcb had been reset several times blowing the CPC clear.

 

[westward10]

Never assume an rcd will prevent you getting an electric shock.