DIY Doctor

split load consumer unit

Postby andylad303 » Fri Sep 23, 2011 8:25 pm

Hi, could someone please advise me. I have wired my sons garage up ( radial) with 2 double sockets and a light. I have fitted a 2 way c/u in the garage which is non RCD. When I came to connect up in the house to the main c/u I noticed that there are no spare ways on the RCD protected side of the c/u, though there are 3 spare ways on the non RCD side. I believe the garage must be RCD protected, could I connect up to the ring 32amp for the upstairs sockets as they are hardly used or would I be able to move an MCB from the RCD side to the non RCD side. The protected side consists of 40 amp shower MCB, 3 32amp ring main MCB's and a 16amp MCB for the combi boiler. Is it possible for the combi boiler to be on the non protected side? Any advice would be grateful.
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Simply Build It

Postby ericmark » Sat Sep 24, 2011 8:59 pm

Your best way is to use a RCBO which is a RCD and MCB combined. They may not fit in original board as they are longer than a MCB but should fit into the garage board without a problem.

Rules say you can still use an installation which does not comply with latest regulations but you can't down grade a circuit to old regulations once it has complied with new one. Today near every circuit is RCD protected either because it has cables buried in wall at less than 50mm or it supplies a socket of less then 20A or it supplies something in a bathroom all which now need RCD protection including bathroom light.

Assuming the main cable to garage is SWA then that does not need protecting so the RCBO could go in garage or change main isolator in garage to a RCD.

You will of course when filling in the installation certificate for the LABC have to test the RCD and insert the tripping times etc. Also all the loop impedance figures so there is no way to cheat it has to be correct to get the completion certificate from council. So you can't use ring main really.
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