To Earth or Not To Earth.. that is the question?

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Trailer Boy - Electrician.
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Friday morning popped in to see a customer who wants an additional light switch fitted to make a set of lights two-way switching...
obviously wants a switch to match the existing decorative metal switches...

So I opened the one I will need to extend to check what make it is...

Find its a LAP...

But also find an unused terminal on the top left of the picture!!!!!!!!!!!!!!!

I may be wrong..
But I am pretty sure that little bit of paper that falls out when you open the switch normally says..
This accessory MUST be earthed!!

Is it just me, or is this a bit of piss-poor lazyness ?


LAP SWITCH.JPG


Apparently this was re-wired a couple of years ago!
 
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Arguably, with a metal back box and one of the lugs is not adjustable, it will be earthed through the mounting screw.

Still lazy not to fit a link.
 

BorisJ

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All metal switches should be earthed using the CPC in the connecting cables. An additional link can be connected to the back box, though not strictly necessary.
 

binky

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I would use that earth terminal rather than the back box one, but if you have a single fixed lug, then there is no need for an additional earth bond. If you have 2 floating lugs, then it must be bonded. Can't remember where I read that many years ago, but I don't think it has been changed since.
 

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Trailer Boy - Electrician.
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My general preference has always been...

A metal light switch IS an exposed conductive part and MUST be earthed

A metal back-box, (once the accessory is fitted) is NOT exposed in NORMAL use.

If an accessory front has been opened up.
Then.. Unless you have some really good proven reasoning..
the power should be OFF anyway, before you open the switch !!!!!!!!!!!!

Basically I would not use the back-box earth as the primary source of CPC termination when an accessory ALSO needs a CPC connection...
 
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