Addng cpc to two core lighting circuit

[LlandrilloSpark]

Fellas is it permissible to run a single 2.5mm in a loft or do really need double insulated?, there has been an attempt to add an earth to the circuit before but they missed the switches out and some fittings are 32Ohm R1+R2, it's in a bungalow so should be easy

 

[Adam W]

I think it has to be over 6mm if you're installing it without mechanical protection.
Could you just rip it out and do it all in bog standard T&E? Might be easier, neater, cheaper etc.

 

[LlandrilloSpark]

I had thought of a circuit rewire but only 4 lamps are effected and the switch back boxes have plastic lugs so they don't even technically need earthing if the patress screw doesn't touch the back box, and all the switched are PVC, cheers for the 6mm advice

 

[Johnny-G]

It has to be 4mm min if it hasn't got mechanical protection (543.1.1) but what's usually the hardest part adding one is that it has to be incorporated in the same wiring system or in the immediate proximity of the live conductors (543.6.1) which means dropping one down to switches etc so it's probably easier to just rewire.

 

[Trevor R]

Think even the back boxes have to be earthed even if not technically required now to allow for somebody putting in metal casing switches in the future .

 

[Paul.M]

A cpc needs to run the full length of the cable run regardless of class 1 & 2 fittings.