Replacing metal light switch with plastic one, no earth socket?

Am replacing a metal light switch for plastic one, from the wall have three cables, red (live) black (Neutral) and Green/Yellow ( Earth)

On the switch have only 2 holes, COM and 1WAY, I assume RED wire goes in COM and Black Wire Goes in 1WAY, but what do I do with earth wire?, just put it in a block out of the way?


Distinguished Member


Well-known Member
Should be a brass lug on the back box, connect it into that.


Active Member
If there is no earth terminal on the switch there maybe a terminal on the metal box in the wall?
If you are replacing a metal switch with a plastic one, if there is a metal back box, then this must be earthed using the earth wire.

If its a plastic dry lining box, then put a connector on it.


Novice Member
I was replacing the metal switch for a plastic and as the earth screw on the metal back plate was not turning I sprayed with wd40. I then checked how safe that would be if I turned it back on and people are saying not to use wd40 with electrical connections. Am I safe to turn back on if I let it dry out??


Distinguished Member
WD40 is petroleum based, so wait until it dries off a bit, just in case.

For future reference, if the screw is jammed, just cut the cable and then re-do the connection. It's only a case of cutting back the insulation.

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