Metal back boxes and cpc

[1john]

The fixing screws should not be relied as an earth for the plate.

Someone could change them to nylon leaving the plate unearthed.

The plate could be removed by say a decorator and when replaced the screws are not correctly tightend, leaving the plate inadequately earthed.

For the sake of a few pennies always fit an earth wire.

are you suggesting here that the CPC's should be ran to the back box and the fly lead forward to the accessory?

If not then it makes no difference if nylon screws are fitted.

If the decorator replaces it not tight enough then he has altered the design of the installation and even still i dont beleive there would be inadaquate continuity from TWO screws sitting in threads to a bock box, if that were so then we would have fly leads from switch back boxes to plastic light switches to earth ferrals around there the plate screws sit, but we dont.

 

[holmslaw]

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