no earth on dimmer switch

[jolee_39]

Iwant to swop plastic dimmer to metal case dimmer but on removing plastic cover found no earth wire and a wood surround instead of metal box. how do i earth new switch

 

[paulfromswindon]

If your lighting wires are just two core cables (black and red but no earth), then your lighting system will probebly need rewiring - there is no safe or acceptable way to steal an earth from elsewhere. Basically, any lighting circuits with no earths need to be replaced. This is even more of a priority if you have rubber cables (with black outer insulation).

If you do have the rubber cables, please be careful taking off switch plates as the inner insulation can be very brittle.

You may find that there is an earth which has been cut off where the cable enters the backbox and you may be able to terminate the earth if so (and if you can pull some more cable into the switch).

The fact that there is a wooden back-box suggests a very old installation, possibly with rubber cables - these are normally replaced for metal ones when a system is rewired. If you do find rubber cables, do not attempt to pull more wire into the switch, rubber cabling is now very fragile.

I would suggest you get a wiring check, and in the meantime, do not fit any metal light fitting or switches. Based on your description of the issue, I would not take any risks, and ensure you turn the juice off before looking in switches if the wiring is very old.

Cheers

Paul