Metal switch plates and earth

[superclaret]

When replacing a switch plate with a metal one, where the back box is metal and has an earth connection...should I connect the earth from the back box to the switch plate earth or leave as is?

Thanks

 

[Simon35]

I would connect the earths from the incoming cables to the switch plate and take an earth from there to the back box.

Although, if the back box has at least one fixed tab then it will usually be earthed via the screws.

 

[superclaret]

I would connect the earths from the incoming cables to the switch plate and take an earth from there to the back box.

Although, if the back box has at least one fixed tab then it will usually be earthed via the screws.

Thanks Simon, that is what I thought but just needed clarification from someone

 

[Taylortwocities]

It may be earthed when the screws are in place, but there is no guarantee of the quality of the connection. If there is an earth terminal, it MUST be hardwired to earth.

 

[plugwash]

AIUI it's considered acceptable to rely on a screw screwed into a fixed lug to take an earth from the accessory to the backbox but not vice-versa. Presumablly because the accessory is considered a much higher risk than the backbox.

 

[ban-all-sheds]

Or because it is the switch plate which is the exposed-conductive-part, not the box.

 

[sparkwright]

When replacing a switch plate with a metal one, where the back box is metal and has an earth connection...should I connect the earth from the back box to the switch plate earth or leave as is?

Thanks

To clarify, if you haven't got a fly lead to fit between the box and the metal switch, you would remove the the earth wires from the box and connect to switch earth terminal.

Fitting a fly lead between the box and switch faceplate is the best way though, if you can get some wire.

 

[stillp]

Although, if the back box has at least one fixed tab then it will usually be earthed via the screws.

Then it won't be earthed when it is removed, which is the time that presents the greatest risk.

 

[EFLImpudence]

Then it won't be earthed when it is removed, which is the time that presents the greatest risk.

At least it will not present a path to earth should you touch the live wire and the back box - especially with one hand to each.

Either way - it should not be accessible with the power on.

 

[stillp]

I agree with your second statement, but not your first!