Main Breaker trips

[ciscodave]

I am extending a ring main upstairs, I switched of the circuit breaker for the ring, but when I disconnect the earth cables in the socket I am going to extend the ring from, the main Breaker RCD trips and I loose power to all my house. I am unable to get the breaker to stay up unless I connect the earth cables back together and the trip stays on ok. Is this normal? I have never seen this before.

One thing to add I did find a additional earth cable connected other than the expected ring in and ring out earth cables, but I am unsure of where it goes to.

[kbrownie]

ciscodave,
they will trip RCD even though your breaker is open.
Best solution is either to tape ends of conductors you are removing so they don't touch each other while carrying out the work or disconnect cables at CU supplying the circuit.
Your addtional earth needs more investigation, could be a case of supplementary bonding unusual in socket circuits or the earth being used for another circuit, this should not be done.
So get it checked out.
Also to add, that extending a ring circuit is not notifiable unless in a kitchen or special location and still needs a minor works cert regardless of location.
KB

[ciscodave]

Thanks for the help, I will get the earth checked out. Once again many thanks

[ciscodave]

[quote="kbrownie"]ciscodave,
they will trip RCD even though your breaker is open.
Best solution is either to tape ends of conductors you are removing so they don't touch each other while carrying out the work or disconnect cables at CU supplying the circuit.
Your addtional earth needs more investigation, could be a case of supplementary bonding unusual in socket circuits or the earth being used for another circuit, this should not be done.
So get it checked out.
Also to add, that extending a ring circuit is not notifiable unless in a kitchen or special location and still needs a minor works cert regardless of location.
KB[/quote]

Thanks for the reply, I will get the earth checked out. Many Thanks