Light switch without earth wire

[daveok77]

Hi everyone,

In a bedroom, I have two single light switches that control one light (one by the bed and one as you come in by the door). I am fitting new stainless steel face plates to them. Did the one by the bed first and that had an earth wire connected to the back box so could fix that to face plate. But the one by the door has no earth wire as per attached picture. I'm assuming this will need to be earthed as well even though connecting to same circuit as other earthed switch? Any advice appreciated?

 

[westward10]

What is the hexagonal bush fitted to the back box made of, brass or plastic.

 

[daveok77]

What is the hexagonal bush fitted to the back box made of, brass or plastic.

Hi there. It's definitely metallic and when I scratched the top of it with the driver it did appear to be brass.

 

[Dave OCD]

It may well be that the wiring is enclosed in a steel conduit system which is being used as the cpc [earth]. Are you in a flat ? The best way to verify this would be to get an electrician in for an hour as test equipment is needed to confirm or otherwise.

 

[westward10]

So the switch is wired using steel conduit which should be earthed and is providing the cpc. If any alterations have taken place there is a possibility this conduit is no longer earthed, if it is the switch needs a cpc to the back box however the back box has no earth terminal to facilitate this. As a above I would recommend the services of an electrician to verify the effectiveness of the conduit system including the switch you have already replaced.

 

[7029 dave]

Looks like metal clad surface box sunk in, also singles out of that male bush.

 

[Pete999]

Hi everyone,

In a bedroom, I have two single light switches that control one light (one by the bed and one as you come in by the door). I am fitting new stainless steel face plates to them. Did the one by the bed first and that had an earth wire connected to the back box so could fix that to face plate. But the one by the door has no earth wire as per attached picture. I'm assuming this will need to be earthed as well even though connecting to same circuit as other earthed switch? Any advice appreciated?View attachment 64564

Looks like a single cable install using solid conduit, is this the case if so the conduit could be used as the cpc

 

[Dave OCD]

But only after verifying that the conduit is actually earthed Pete.

 

[7029 dave]

But only after verifying that the conduit is actually earthed Pete.

Until so, I would fit plastic.

 

[Pete999]

But only after verifying that the conduit is actually earthed Pete.

Agree but if the entire system is solid conduit throughout then an earth will be available at all points won't it? jus t need a fly lead to each accessory won't it? Only after proving by tests that the conduit is suitable to act as the cpc, earthing the tube at the DB.

 

[westward10]

Agree but if the entire system is solid conduit throughout then an earth will be available at all points won't it? jus t need a fly lead to each accessory won't it? Only after proving by tests that the conduit is suitable to act as the cpc, earthing the tube at the DB.

See #5.

 

[daveok77]

Thanks everyone for your replies. I'll leave the plastic face on for now until I get it tested.

 

[littlespark]

Is there another switch back to back with this one? I’m thinking conduits normally come in the top face backbox rather than rear.

Might a cpc there that hasn’t been brought through.

surprised it’s a metal clad surface box been used?

 

[Ziggie]

if the back box is earthed through the conduit then you could use a self drilling screw into the back-box with a ring crimp on one end of a piece of earth wire from it to the switch. Some back boxes don’t have an earth terminal.

 

[westward10]

if the back box is earthed through the conduit then you could use a self drilling screw into the back-box with a ring crimp on one end of a piece of earth wire from it to the switch. Some back boxes don’t have an earth terminal.

Very professional.