Earths to 3 gang light switch

[mdh1]

Hi,
Do all switch cables in a 2+ gang light switch need to be earthed?
I can't see any reason all earths are needed to earth the back box and switch but can not find anything on-line stating this.
I am changing all my switch cables to twin&E but one cable will be a nightmare to change.
Cheers

 

[SaladFingers]

All cables need a circuit protective conductor, the earth conductor.

They should all be terminated together in the parking terminal in the back box. Metal boxes must be earthed and metal switch plates must be earthed.

 

[phatboy]

All cables need a circuit protective conductor, the earth conductor.

They should all be terminated together in the parking terminal in the back box. Metal boxes must be earthed and metal switch plates must be earthed.

Not totally correct I'm afraid.... all cables need their CPC to be connected, and all metal switch plates need earthing. If you earth the metal switch plate (or a plastic double socket, that will have earth terminals, then you do not need to earth the metal backbox - however it is a good practice.....

 

[SaladFingers]

All cables need a circuit protective conductor, the earth conductor.

They should all be terminated together in the parking terminal in the back box. Metal boxes must be earthed and metal switch plates must be earthed.

Not totally correct I'm afraid.... all cables need their CPC to be connected, and all metal switch plates need earthing. If you earth the metal switch plate (or a plastic double socket, that will have earth terminals, then you do not need to earth the metal backbox - however it is a good practice.....

So, you say not totally correct, then go on to say what I've said,

with the exception of 'a plastic double socket, that will have earth terminals, then you do not need to earth the metal backbox'.

 

[Chri5]

All cables need a circuit protective conductor, the earth conductor.

They should all be terminated together in the parking terminal in the back box. Metal boxes must be earthed and metal switch plates must be earthed.

Not totally correct I'm afraid.... all cables need their CPC to be connected, and all metal switch plates need earthing. If you earth the metal switch plate (or a plastic double socket, that will have earth terminals, then you do not need to earth the metal backbox - however it is a good practice.....

isn't that what he said?


OP You could write up the pita non earthed cable as a noted item and then MUST use a plastic switch. However, it's worth the effort since any new buyer will likely deduct monies to sort it (and the decoration and fabric damage).

So pita it might be, but do it right and replace the cable with TE.

 

[mdh1]

Thanks all.
I was hoping that in this 3 gang switch as the other 2 switch cables will be changed to TE, therefore protecting the back box/switch plate, this would mean I wouldn't have to change the 'difficult' cable.
Then I read somewhere else about not 'borrowing' earths.
Best get up in my stupid low pitch loft, move a load of insulation, lay flat on my stomach, and try and see if I can pull a cable across a sloping raised landing ceiling, doh!

 

[RF Lighting]

Can you tie a new cable onto the old one and use the old cable as a draw wire to save scrabbling about in the loft space?

 

[mdh1]

It doesn't budge at all at the moment.
I might have to get a mate round to see if we can do this from the 2 flat ceilings either side of the raised landing above the stairs.
Probably looks like I will have to take down some insulated plasterboard (but the screws aren't budging) and maybe some solid insulation to get access to this cable.
I had hoped that someone would say that as the other 2 cables to the 3 gang switch are grounding the back box and front plate (if changed to a metal one) I wouldn't have to get a CPC to the 3rd cable -(but no such luck ;-(