earth in lighting circuits

[linnsound]

replacing old brass dimmer for plastic one way switch. is leaving the earth in choc block for potential further brass plates the standard practice?
on a similar note when extending a switch i found there to be no earth ( or maybe chopped back very neatly ) on the existing switch cable- this was only switch cable so was not forming any part of earth continuity, so with the new t&E extensionn i chopped the earth back. ok in your opinions?

 

[Space cat]

replacing old brass dimmer for plastic one way switch. is leaving the earth in choc block for potential further brass plates the standard practice?

Is there no earth terminal in the back of the switch box? If you have a metal back box in there, a loose wire could make it live - along with the screws holding the switch.

on a similar note when extending a switch i found there to be no earth ( or maybe chopped back very neatly ) on the existing switch cable- this was only switch cable so was not forming any part of earth continuity

This statement is at odds with your first one. If there was a chopped back earth in there it should have been available for use with any future brass switch. If the back box was metal, it should have been connected there. This is still the case if you put a plastic blanking plate on. Think about the screws.

so with the new t&E extensionn i chopped the earth back

I would have looked for the earth in the existing cable and extended it.

 

[linnsound]

hey space cat.

nope it was a dry lining box with no earth terminal - the earth was originally going to brass dimmer earth.

The 2nd point was in my dads property. Again the back box was not metal it was plastic with no terminal( probably old lighting wiring - so not going to rewire for a switch move surely?). so plastic back box and blank plate.

if it is old wiring though( obviously i could search forever for the earth in the cable and never find it - even ithough there wasn't enough slack to do so) the extension of the switch over the door frame would not benefit from an aearth as there is no earth in the existing wiring, no?

thanks for your reply space cat

 

[Space cat]

nope it was a dry lining box with no earth terminal

I see it now. I've used them before and there's nowhere to connect an earth wire - and nowhere on a plastic switch either. You were right to put the earth in choc block for future use. If you look carefully you'll see that it would be almost impossible for a loose wire to come into contact with either of the switch fixing screws but ---

If you want to be 100% safe you could use plastic screws, which brings me to this:

if it is old wiring though( obviously i could search forever for the earth in the cable and never find it - even ithough there wasn't enough slack to do so) the extension of the switch over the door frame would not benefit from an aearth as there is no earth in the existing wiring, no?

It's possible that your dad's lighting circuit has no earth wire. There was a time when all lights (and a lot of sockets) were wired this way. I have a vivid memory of my mother plugging her iron into an overhead light socket. We even had an adapter so that you could use the light at the same time. From what I've read on this forum, some lighting circuits were rewired with nice new PVC insulated flat twin cable - but with no earth! Penny pinching or what?

If this is what your dad's got, think about scheduling a rewire at some convenient point. Take a look in the CU at the cables for the lighting circuits. If there are no earths in there, you'd be wasting your time looking for one in that old switch box.

Meanwhile, have a look around the rest of his lights and switches. Somebody might have fitted an unearthed metal one somewhere - and don't forget those screws. A metal screw in a metal back box can easily become live!