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Discuss Drilled cable concerns in the Electrical Forum area at ElectriciansForums.net

SImon J

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Just a bit nof a supplementary to this if I may... I was fitting a new bathroom light yesterday in an internal bathroom without windows so too dark to see clearly where cables ran on visual inspection of the back box. It's also a concrete ceiling, so was really tough to drill. I'd switched off the lighting circuit at the board but on one of my drill holes, there was a bright flash in the drill, a loud pop and the RCD for the sockets tripped.

I reset the sockets RCD, the drill worked fine and, after I'd finished and switched the lighting RCD back on, the light came on fine. I've tried to reassure myself that, as the lighting circuit was switched off, it was maybe the drill over-working rather than me puncturing a cable (why would it short if no power?) but I'm not so sure. Despite the gloom, on closer inspection of the back box, it did look like there might be cable running roughly in the direction of the drill hole.

I'd really appreciate any feedback from someone who knows what they're talking about (rather than my uninformed guesswork!) Thanks
 
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pc1966

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Just a bit nof a supplementary to this if I may... I was fitting a new bathroom light yesterday in an internal bathroom without windows so too dark to see clearly where cables ran on visual inspection of the back box. It's also a concrete ceiling, so was really tough to drill. I'd switched off the lighting circuit at the board but on one of my drill holes, there was a bright flash in the drill, a loud pop and the RCD for the sockets tripped.

I reset the sockets RCD, the drill worked fine and, after I'd finished and switched the lighting RCD back on, the light came on fine. I've tried to reassure myself that, as the lighting circuit was switched off, it was maybe the drill over-working rather than me puncturing a cable (why would it short if no power?) but I'm not so sure. Despite the gloom, on closer inspection of the back box, it did look like there might be cable running roughly in the direction of the drill hole.

I'd really appreciate any feedback from someone who knows what they're talking about (rather than my uninformed guesswork!) Thanks
You really need to get that properly checked out, it might have caused damage that is not immediately apparent but makes something possibly deadly later one, for example the drill and/or arc might have opened the CPC (earth wire). The simple fact you could reset the breaker does NOT mean no lasting damage has been done.

Really it is time to get a professional out to check what has happened. You are not the first to do that, and you won't be the last, but please make sure the system is safe before long!
 

littlespark

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I would advise you get this checked out, pronto, immediately and ASAP..... if not sooner.

The fact the socket rcd tripped sounds like you disturbed the cable.
It may reset ok, and even have power, but you may have drilled straight through the earth wire.
 

Pete999

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Just a bit nof a supplementary to this if I may... I was fitting a new bathroom light yesterday in an internal bathroom without windows so too dark to see clearly where cables ran on visual inspection of the back box. It's also a concrete ceiling, so was really tough to drill. I'd switched off the lighting circuit at the board but on one of my drill holes, there was a bright flash in the drill, a loud pop and the RCD for the sockets tripped.

I reset the sockets RCD, the drill worked fine and, after I'd finished and switched the lighting RCD back on, the light came on fine. I've tried to reassure myself that, as the lighting circuit was switched off, it was maybe the drill over-working rather than me puncturing a cable (why would it short if no power?) but I'm not so sure. Despite the gloom, on closer inspection of the back box, it did look like there might be cable running roughly in the direction of the drill hole.

I'd really appreciate any feedback from someone who knows what they're talking about (rather than my uninformed guesswork!) Thanks
T/You may have just nicked a conductor which tripped the circuit, advice if you aren't competent get an Electrician in to check out the wiring, better d\safe than sorry, especially in a Bathroom, might be OK but better check.
 

Pete999

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Just a quick simple question guys,

If you were to say drilling into a wall and their were hidden cable there. What would actually happen if you do drill into one with regards to electric shock, or does the drill usually have some kind of design safety to stop electricution.

Have you done it before?, and what was the outcome?.

Thanks for all your responses
Where are you situated. anywhere close to Northampton?
 

SImon J

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You really need to get that properly checked out, it might have caused damage that is not immediately apparent but makes something possibly deadly later one, for example the drill and/or arc might have opened the CPC (earth wire). The simple fact you could reset the breaker does NOT mean no lasting damage has been done.

Really it is time to get a professional out to check what has happened. You are not the first to do that, and you won't be the last, but please make sure the system is safe before long!
 

SImon J

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Where are you situated. anywhere close to Northampton?

T/You may have just nicked a conductor which tripped the circuit, advice if you aren't competent get an Electrician in to check out the wiring, better d\safe than sorry, especially in a Bathroom, might be OK but better check.
Thanks for all the really helpful replies guys - I really appreciate it and will take your advice pronto
 

Darkwood

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I think the risk here is loss of earth continuity in the circuit, given its a concrete ceiling and cables most likely buried in plaster then the risk of fire is minimal even in a fault condition, given we may have a bad earth now it still should be tested and verified asap.

PS - I have relocated all recent posts into a new thread, the thread they were added to was 13yrs old and concerned another similar incident.
 
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