metal light switch

[tellytv]

Hi,
Was wondering if anyone could help, I'm replacing an old light switch and the new one says on the back "must be earthed"

however if you look t the photos below the old switch hasn't got a earth cable in, but theres one in the wall, does this mean it's earthed and just a case of switching the old wires over to the new plate?

 

[Crofton Gas]

You need to add a earth wire from back box to light switch.

 

[terryplumb]

The earth conductors ,currently in the metal back box terminal ,would now go to the earth terminal on the metal switch plate.

 

[mwatsonxx]

Do what crofton gas has said, terryplumb is wrong.

 

[terryplumb]

No I ain't.

 

[ban-all-sheds]

Do what crofton gas has said, terryplumb is wrong.

No he isn't.

 

[terryplumb]

The use of a flying earth link was put to pasture some time ago mate ,get with it.back box earthed via mounting screws.

 

[mwatsonxx]

The use of a flying earth link was put to pasture some time ago mate ,get with it.back box earthed via mounting screws.

By who, mate, some contracting organisations money saving tip. People will die, always install a flying lead, mate.

 

[ban-all-sheds]

Which regulation requires it?

The box has a fixed lug.

How could someone die?

 

[mwatsonxx]

The earth conductors ,currently in the metal back box terminal ,would now go to the earth terminal on the metal switch plate.

That means the back box is no longer reliably earthed.
What happens when when fixing screws are changed to nylon? or loose fixing screws, the back box is no longer earthed. Thats what could and will kill someone

 

[bernardgreen]

the back box is no longer earthed. Thats what could and will kill someone

How would a person make contact with the back box without first removing the metal switch. They will be holding the metal switch as they remove it, it has to remain earthed.

Putting the earth wires into the terminal on the switch with a fly lead to the back box earth terminal reduces the risk of the metal switch not being earthed when removed from the back box.

 

[Iggifer]

Plus that box has two adjustable lugs so the earth path from plate to box would be rubbish.

Flying lead is the way to go

 

[JohnW2]

Do what crofton gas has said, terryplumb is wrong.

Not 'wrong', but many would prefer to have an additional wire (from the back box) to the switch, rather than removing the earths from the back box (transferring them to the switch) and then relying on the faceplate screws to earth the back box.

Kind Regards, John

 

[ban-all-sheds]

Plus that box has two adjustable lugs

Does it? Didn't, and not sure I can, see that.

 

[ban-all-sheds]

Not 'wrong', but many would prefer to have an additional wire (from the back box) to the switch, rather than removing the earths from the back box (transferring them to the switch) and then relying on the faceplate screws to earth the back box.

There should be no danger of the back-box becoming live when the switch is not screwed on.