DIY Doctor UK DIY Forums

Hi,

I'm fitting a flush fit underfloor heating thermostat into a metal back box but noticed that there is no earth wire. I know that metal boxes have to be earthed but all the plastic boxes are for dry walls. Is there anything specific for this situation or should I just adapt a dry wall back box ?

Please help.

Thank you

No earth wire from what?

Remote stats are usually double insulated, and the control cable should have an earth.

You don't need an earth for separated extra low voltage (SELV) equipment, but for low voltage (230 volt) even if not connected an earth needs running, at one point pre-1966 you could have lights without an earth, but that changed in 1966.

So if mains voltage be it a plastic or metal back box there needs to be an earth.