Bonding

[dandymam]

My consumer unit is split and has two RCD's protecting all the circuits.

The main earthing is a single cable from the main earthing terminal connecting the gas and incoming cold water.

I have a combi boiler, but I cannot see the any hot water pipe earthed.

Is that normal?

 

[ricicle]

The main earth to your property is (hopefully) not obtained from the gas or water pipe. The wire to those is explained below. There is no requirement to bond a hot water pipe unless it enters the property from outside.

//www.diynot.com/wiki/electrics:main_equipotential_bonding

 

[dandymam]

Thank you. I have a main earth coming in from the electricity provider. This goes to a terminal block. From this terminal block, an earth goes to the consumer unit, and also a separate earth goes first to the gas pipe and continues (unbroken) to the incoming water supply. It basically looks like the picture on your link.

I suppose I am thinking about the hot water pipe coming from the combi boiler (and come to think about it the radiator pipes) as I cannot see any earth on these???? Are they needed???

 

[JohnW2]

Thank you. I have a main earth coming in from the electricity provider. This goes to a terminal block. From this terminal block, an earth goes to the consumer unit, and also a separate earth goes first to the gas pipe and continues (unbroken) to the incoming water supply. It basically looks like the picture on your link. I suppose I am thinking about the hot water pipe coming from the combi boiler (and come to think about it the radiator pipes) as I cannot see any earth on these???? Are they needed???

The (only) purpose of the main bonding is simply to ensure that any pipe entering your house from outside is at the same potential as your installation's earth terminal, and hence the 'earths' throughout your installation (i.e. to ensure that a potential different from that of your installation's earth is not introduced from outside the property by pipes entering the property). Any other pipework which is wholly within your property cannot possibly introduce any other potential ('from outside') and therefore does not need main bonding. In practice, of course, if your house has copper plumbing, all of the pipework will end up effectively 'electrically joined', anyway.

Kind Regards, John

 

[sparkybird]

The need for supplementary bonding (eathing) to hot/cold/rads is negated by the fact that all your circuits have RCD protection

So no, it's fine
SB

 

[swampy2]

What happens if RCD fails and there is no supplementary bonding in place.

 

[JohnW2]

The need for supplementary bonding (eathing) to hot/cold/rads is negated by the fact that all your circuits have RCD protection

Well, that's certainly one of the conditions for omitting supplementary bonding in special locations. However, I suspect that the combi-boiler which concerns the OP is probably not in his bathroom, anyway.

Kind Regards, John

 

[JohnW2]

What happens if RCD fails and there is no supplementary bonding in place.

Nothing, unless a fault arises in the installation.

Kind Regards, John

 

[dandymam]

Thanks everyone.

So I take it that the hit water and central heating don't need "bonding".

Combi is in kitchen.