Earth Bonding Ask questions and find answers to many subjects relating to electrics and electrical work

[robster281]

Hey guys, i have had my gas meter moved and subsequently they removed my earth bonding. So question, is it right to use 10mm cable direct from the consumer unit to the house side of the incomming gas pipe? also my combi is located just above but on the inside, can i run a similar 10mm wire from the earth clamp on the gas pipe up to the pipes coming out of the combi??and then link then across?? or can i just link then using the earthed incomming gas pipe??
sorry for any confusion!!
Cheers

[sparx]

yes within 600mm of flex pipe b4 any branch or tee, the boiler pipework only needs to be cross bonded, no need to link from main 10mm, use min. of 4mm, but check as most combies have all pipes connected through a common gland plate which is then connected to earth wire internally attached to boiler earth wire, if poss. test continuity from boiler supply earth wire to each pipe, if good no further bonding should be reqd.
Sparx

[robster281]

Thanks for the reply Sparx!
Another question though lol, earth bonding/power for the combi is from a fuse spur on the ring main im assuming this is ok?
Also my incomming water supply is a plastic pipe which then obviously joins to copper under the sink, once again am i correct in assuming a 10mm main earth is req?

Thanks

[sparx]

Yes & yes...
short and sweet this one, regards Sparx

[robster281]

Wow these questions are too easy i must try and get more technical lol.
Final easy question, equipotential bonding in the bathroom. Am I correct in using 4mm earth? also would I be right in assuming i need an 3 amp switched fuse spur outisde the bathroom for my extractor fan?taken from the bathroom lighting circuit using 1.5mm twin and earth.

Cheers

[sparx]

yes 4mm is min. if not 'mechanically protected' ,can't see it in conduit but if it was then min. is 2.5mm
you can use 'switched-fused connection unit' as we are told to call a fused spur these days, but a D. Pole switch will do instead unless you have a timer over run fan which needs a three core and earth, when you need a fan isolator switch which has three poles switched.
NEXT!.....
Regards SPARX

[robster281]

Great thanks for the answers there Sparx!
Lets get more technical lol Inside the CU, on the earth terminal block is there a correct order for the connection of the earth terminal from the lighting, sockets, main earth bonding etc??or is order not important?

Regards

[Jeffmo]

Your main earth and equi cables are generally together in a three , marked with earth symbol, the others now are normally numbered to coincide with neutrals .Sparks may tell you different , he knows best .Regards Jeff

[sparx]

yes earths and neutrals supposed to follow same order as lives so later tests /mods etc can identify, but lots of CU's have earth bar numbered wrong way!
as for bonds etc some bars have 2/3 holes larger at one end to take 10/16 mm conductors, it does not realy matter if not which end u start as long as circuit CPC's are in correct order.
Regards SPARX