No the screws are ok if one fixed lug but if you loosen say to decorate then front plate not earthed, of course the best way is to connect the circuit earth direct to switch plate then you don't need 'fly lead'
[quote="mao1"]Thanks SPARX I figured that would be the answer better safe than sorry![/quote]
All metal switches should always be earthed and all metal back boxes regardless. As an electrician my only defence in a court of laws as that "i followed the wiring regulations"
Just to put the records straight reg, # 543-02-02 & 05 say you can use the metal conduit if continuous as an earthing conductor but if you do so, then reg. 543- 02- 07 says then you must connect an earthing conductor from the earth term. in box to front plate of any metal accessory, This is NOT reqd. if the circuit protective conductor is taken direct to the earth term. of the front plate as even if accessory unscrewed the CPC will still be connected & the back nox becomes 'isolated metal work'
I quote the IEE not the NICEIC version of what they would like the regs to say!
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