I have put two new lights in a room, they both go to a double switch. One light causes the MCB to pop when the light switches on. After further investigation i found it only happens when the earth from the switch cable is connected in the ceiling rose. Therefore i have come to the conclusion that the earth cable is coming live when the switch is made. Can i just cut the earth back in the ceiling rose and not connect it? I can earth the switch box because i can use the earth from the other light. Will this pass an inspection? I dont want to have to chase the cable out as just had it plastered.
Will it pass inspection?
- Thread starter daveturnbull
- Start date
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NO NO NO.
That is simply masking a dangerous fault.
You need to find where the live to earth fault is and correct this. It maybe inside an accessory, the light fitting etc etc.
It would not pass an inspection if it was picked up.....
That is simply masking a dangerous fault.
You need to find where the live to earth fault is and correct this. It maybe inside an accessory, the light fitting etc etc.
It would not pass an inspection if it was picked up.....
Great idea, just disconnect the circuit protective conductor... Far easier than fixing a potentially fatal electrical fault.
Ok i get the picture, i just thought with the earth being insulated it wont actually cause a problem if it wasnt connected at either end. I have chased up the wall above the switch and cant see anything wrong. Although i only went as far as the coving so guess i will have to remove that and hope it is there, otherwise the ceiling will have to come down!
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All that in 30 mins? You put us professionals to shame
I would suspect a termination or a nail etc - Is the cable new or old? What replastering has been done?
I would suspect a termination or a nail etc - Is the cable new or old? What replastering has been done?
i chased up the wall earlier today as wanted to put it right. The cable is new as its part of my extension. I only did the second fix today.I first thought i had put a nail through it when covering the cable with tin, but like i said upto the coving it seems ok. However i think where the tin end because it is quite sharpe it might have cut into the cable there. The rest goes through the joist and to the light so cant see how it could have got damaged there. Where would you start if you had to chase back or is it pot luck?
have you actually disconnected the cable both ends and tested it to earth?
an insulation test is also a good idea before plastering, and again before connection..
an insulation test is also a good idea before plastering, and again before connection..
No i havent done that. can you explain more what you mean? I regret now not doing an insulation test.
It would appear the fault is a live to earth short. So disconnecting the earth in the ceiling rose will mean a lot of metal work will become live, including the screws that you can touch on the switches and the whole switch plate if they are metal switches.
LETHAL
LETHAL
Bernardgreen,
Not really because the earth cable in question is only part of the switch cable, so i was not going to connect it to anything just cut it back to the insulation. I could still earth mounting box and cover with the other earth terminal as it it a double switch. That was my question, if i cut it back and its insulated this shouldnt cause any danger, however after reading the comments this is a big No No.
Not really because the earth cable in question is only part of the switch cable, so i was not going to connect it to anything just cut it back to the insulation. I could still earth mounting box and cover with the other earth terminal as it it a double switch. That was my question, if i cut it back and its insulated this shouldnt cause any danger, however after reading the comments this is a big No No.
in order for the earth wire to become live it's either a dodgy connection somewhere or a piece of metal is connecting live to the earth.. this may be a screw or nail, or even as you sugested the sharp edge of the capping ( good practice to double the ends over by the way.. not that the sugestion helps now in hindsight.. ).
this means that whatever piece of metal does the connecting is then live also..
damp in the walls / ceiling can then cause a nasty shock as was mentioned somewhere on another thread. ( some guy was getting a shock from his plaster on an outside wall )
as for what I meant in my previous post, i'm unsure whether you were being sarcastic but just in case you weren't then disconnect the switch wire and it's ascociated earth from the switch and ceiling rose and see if the 2 wires have continuity to each other.. if they do then it's definitely a screw or something through the cable.. if not then you connected it up wrong somewhere..
this means that whatever piece of metal does the connecting is then live also..
damp in the walls / ceiling can then cause a nasty shock as was mentioned somewhere on another thread. ( some guy was getting a shock from his plaster on an outside wall
)as for what I meant in my previous post, i'm unsure whether you were being sarcastic but just in case you weren't then disconnect the switch wire and it's ascociated earth from the switch and ceiling rose and see if the 2 wires have continuity to each other.. if they do then it's definitely a screw or something through the cable.. if not then you connected it up wrong somewhere..
Coljack,
Wasnt being sarcastic. Thanks for your help. hopefully will sort it tomorrow.
Wasnt being sarcastic. Thanks for your help. hopefully will sort it tomorrow.
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