Bonding a radiator

I need to do some bonding im my bathroom (currently has none) and understand I need to connect to the pipes running to the radiator. Do I connect to both flow and return or just one of them?

Also, where is the connection usually made? Does it have to be above floor level or can it be under the floorboards?

Thanks

The bonding has to be visible for inspection and maintenance, so not under the floor or plastered into a wall. However, if the copper pipes pass through an adjacent airing cupboard, you can bond them just before they pass through the wall into the bathroom.

You have to bond each pipe (hot water, cold water, radiator flow, radiator return) and, if you have metal waste pipes or soil pipes entering the bathroom, them too. However, once each one of these pipes has been bonded at point of entry, you do not need to bond the same pipe again (so e.g. you do not have to bond the same cold water pipe at the basin, and at the bath, and at the WC cistern). This is because, once it has entered the bathroom, it is not going to pick up any additional voltage.

You have to bond all these pipes to the earth wire of each electrical circuit. This is the lighting, sometime an electric heater, shower pump, central heating pump, immersion heater, electric shower, shaving point and fan (unless they come off the lighting circuit that you have already bonded).

You will find lots more posts and diagrams if you do a search on "Supplementary Bonding"

The "search" button is near the top of this page.

and look here //wiki.diynot.com/electrics:sp...rooms_and_supplementary_equipotential_bonding

just a thought but doesn't that then make the earths into rings?

out to the shower, through a pipe and back down the lighting circuit?

do you then have to do a continuity test on the ends of the "ring"