We've just had our central heating re-done (lots of problems, but that's another story.) The electrician who wired up the boiler and did the earth bonding on all the supply pipes, added a sticker saying (roughly) "earth bonding to bathroom radiator was not done as resistance to pipes measured 0.00 ohms". They replaced the radiator as part of the heating install, but just connected it to the existing pipework. I'd not thought about it up to this point, but the bathroom was remodelled a few years back, and they moved this radiator and used plastic pipes to do so. Sure enough, putting a multimeter from the radiator to the cold water pipes elsewhere in the bathroom shows an open circuit (infinite resistance.) I DO get virtually zero ohms from the radiator to the chrome plated pipes underneath it, but these are connected to plastic under the floor, so it's isolated electrically from the rest of the pipework. So .. should the radiator have been earthed, (probably originally when it was moved) and why?