Cross bonding

[tomnico]

Recently a Corgi registered gas man came round my flat to issue a gas safety certificate and said that the pipes from the boiler needed cross bonding. Apparently they need to be earthed back to the main earth point. My question is, that he has not made it clear whether the pipes need to be earthed back to the whole building's earth block (somewhere downstairs outside) or whether going back to the individual flat's meter is enough? The meter itself is also outside so would I need to go back to the meter (or within 600mm) or is it ok to connect at the point the pipes enter the building?

thanks
Tom

[JohnD]

Have a look at your consumer unit (fusebox). Beside it, there may be an earthing block with several biggish earth wires going into it, including one for the gas and one for the water pipe. If it has, you can use that for the boiler too and it is very easy. If there is no earthing block then the connection could be inside the CU, which being full of live electrical items should not be opened up without proper knowledge.



Unlike the gas, water and bathroom bonding, the bonding of the boiler is not an "electrical regulations" but a "gas regulations" thing.

Is it your own flat, or rented (in which case I would have thought landlord's responsibility)

[tomnico]

Thanks John. I have actually bought the flat to let out so I am the landlord I guess, trying to make it safe for tenants!
Will check it out when I go to the flat tomorrow

thanks again

[baldelectrician]

A main gas bond is required from the point the gas supply enters the dwelling (within 600mm after meter) and for the water within 600mm of the main water valve (inside the flat - after water meter)
These are called main earth bonds.


Supplimentary bonding is required at the combi, all 5 pipes (except blow off-the one that goes outside - not gas)

There is no need to run a main bond to the combi unless the gas supply enters the building there.