Earthing A Bath

[DIY_Dean]

Hi

Whilst replacing my bathroom suite, I noticed that the pipes feeding my basin (correctly) have earth bonding, however there doesn't seem to be any earthing on the pipes going to the bath.

Is this normal? I can't think of any reason why a bath would be any different from a basin in this respect. The house is 10 years old.

Also, as I'm replacing an acrylic bath with a new steel one, does this make a difference to the earthing requirements?

Thanks

 

[JohnD]

The idea of Supplementary Bonding in a bathroom is that you bond all the metallic services where they enter the bathroom, to the Earth Wires of each electrical circuit that enters the bathroom.

Having bonded them all when they come in, you do not need to re-bond again inside, as there is nothing (no wire or pipe that has not already been bonded) that can introduce a potential.

So if you have bonded the hot, cold, and radiator pipes; the waste pipe if it metal, and the soil pipe if it is cast iron, to all the earth wires, you do not need to bond to the bath as well.

Of course, you are not allowed to bring in hair driers or anything on extension leads into the bathroom.

Usually the Hot and Cold to the bath are fed from the same copper pipes as the ones to the basin. If they are copper and have permanent (soldered) joints than you can treat the copper pipe as part of the bonding, as it gives a good electrical connection. Sometimes Shower supplies come in separately, in which case you have to bond them to all the others.

 

[DIY_Dean]

Thanks JohnD, makes sense now

One other thing - the old radiator had an earth clamp attached not to the pipe but to the radiator itself. I replaced it with a towel heater, but there in no way of connecting the existing earth clamp to it (and it would look daft!). Is it acceptable to connect the earth clamp to the pipework leading to the towel heater even though there is PTFE tape between the pipework and the radiator itself?

How do you normally get around this problem?

Thanks again

 

[JohnD]

You put the bonding clamps on the pipes.

You can even bond to the pipes under the bath, or in an adjacent airing cupboard just before they go through the wall. The clamps must be accessible for inspection and maintenance (so not under the floor ot tiled over).

The point about the PTFE on the rad: there is probably quite a good connection (radiator water is quite conductive and it will only have to bridge 1mm or so) but, if by chance the rad was fully insulated, then it would be treated like any other metallic object not connected to anything (for example, a metal towel rail on the wall, which does not need to be bonded).

 

[DIY_Dean]

Thanks for the excellent advice, cheers!

 

[Paul Barker]

Yes I totally agree with all of that which John said.