DIY Doctor

Supplemental earth bonding

Postby brucephipps » Sun Dec 30, 2007 6:14 pm


Could anyone tell me - should supplemental earth bonding be routed back to the earth bus bar in the consumer unit? The reason I ask is because I recently had to take the side panel off my bath to fix to a leaky pipe, and decided to check the earth bonding in the process.

All hot & cold taps for the bath & basin are joined by a 4mm2 cable, but the end of it, is wired into the earth terminal of the light fitting. This is a much smaller conductor (1.5mm2?) and I couldn't help wondering if this was ok, especially with the cable lengths involved.

From my bathroom, a 4m cable would reach from the basin to the consumer unit. As it is, I suspect the overall length of the earth conductor will be much longer than this, given that the lighting circuit will be a radial configuration.

Any advice would be much appreciated.

Many thanks
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Simply Build It

Postby kuzz » Mon Dec 31, 2007 11:17 am

Equipotantiol bonding Is between Your main earth terminal & Your services (Water/Gas).
Suplementary bonding in your bathroom should be between all circuits, hot and cold. so it sounds correct.
However I think they are going to sack off the bathroom bonding in the new edition of the regulations. Something i'm glad of with plastic pipe and fittings becoming more & more popular.
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Postby kbrownie » Mon Dec 31, 2007 4:09 pm

Hi brucephipps, as Kuzz has mentioned installation okay. It's supplementary bonding so no need to go back to CU. The light fitting is most probally outside the zones so may not need it anyway, I'd expect electric showers, heaters, shaver sockets to be supplementary bonded though, if you have them!
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Postby brucephipps » Wed Jan 02, 2008 10:56 pm

Thanks Kuzz & KBrownie. Much appreciated.
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