"BigWallop" wrote in message ...
"Lobster" wrote in message
om...

2. I need to take an earth cable right through the house to the
kitchen sink. Do I need to have a separate, continuous cable going
from the earthing point at the fusebox all the way to the kitchen
(which means going through the bathroom en route) or is it sufficient
to piggy-back the kitchen earth cable on to a clamp on a bathroom tap,
say?

All the pipes which connect to the central heating
boiler, including the gas connection, should also be bonded together at the
closest point where they meet at the boiler. The boiler itself should
provide an earthing lug if the casing and chassis have exposed metal parts,
which most do.

Hmm, my Sime combi is certainly metal! but I can see no sign at all of
an earthing lug. There is a 3-core flex entering the boiler, but
having taken the boiler's cover off, I can see it dissappearing into
its bowels and I'd have to half-dismantle the boiler to trace where
the earth lead is wired to (possibly into the pump?) - surely that
shouldn't be necessary?

If any plastic pipework or joint fittings are used, then the earth bonding
should by-pass it and be connected to the metalwork where any valves or tap
connections have been made to all appliances, this includes all points on
the water and gas distribution systems.

Think this is probably where I was getting confused (Stefek et al!)
abiut taking an earth bonding cable (10 mm2) all the way back to the
fusebox from the bathroom (or indeed the kitchen, if that's where the
water main comes in) ... from what you are saying above, isn't that
exactly what I'd need to do if there is any sign of plastic plumbing
being used (although that isn't the case here, in fact)?

Hope this helps answer some of your questions David. :-))

Absolutely, thanks to you and the others for the advice!
David