Changing a switch to a dimmer.

[Luke Merritt]

Hello, I am changing the fittings in my kids room from an ordinary plastic switch to a brass dimmer switch. However the wiring is different. Currently, there is a black and a red cable however the dimmer switch has a few additions. It has the arrow symbol through a smooth wave, an L2 and an L1 as well as an earth cable input. There isn't an earth cable at all in the wall. Can it be done? What would go where? Am I right in saying an L2 input is for when there are multiple switches controlling a single light.

 

[terryplumb]

Luke ,a metal switch must be earthed,a plastic one does not. options are :- change dimmer for plastic or get a spark to provide an earth. by the way generally you need a deeper back box to accommodate a dimmer.

 

[JohnD]

if there is no earth cable, you mustn't use metal switches or lamp fittings. It is not safe.

this is usually found on houses wired in the 1960's or thereabouts.

 

[foxhole]

Red should be live into switch , black is live out ( L2 can be used) . Are you sure there is no earth as its normal for cable used to be twin and earth.

 

[rsgaz]

get a spark to provide an earth.

It could be earthed by steel conduit, but you should get this verified by an electrician, so it'll just be cheaper and easier to get a plastic dimmer, as has been recommended.

Gaz

 

[JohnD]

Very annoyingly, lots of electricians and householders in the 1960's used t&e, and actually snipped off the earth conductor wherever they saw it. So even if you could find an eighth of an inch of it in your lightswitch backbox, it would probably not be connected to anything at the other end, and all the other bits of lighting cable would be the same.

This has been a source of much rage to following electricians over the last fifty years.

 

[ban-all-sheds]

soi-disant
Very annoyingly, lots of ^ electricians and householders in the 1960's used t&e, and actually snipped off the earth conductor wherever they saw it.