I had a comment on a training course yesterday that someone had been told (by an electrician) that it is no longer acceptable to run a separate single core CPC alongside an SWA cable, and that it had to be a core within the cable.

I couldn't see anything in the Big Brown Book that prohibits use of a separate protective conductor. They state that it may be a single core cable, and provided it is run in the same wiring system as the circuit conductors or in close proximity to it then it should be OK.

Does anyone support the theory that use of a separate CPC is no longer allowed, and if so then which regulation might this contravene?  I can see situations where it may be regarded as not adequately mechanically protected if outside the SWA, but I can also see situations where that would not be a problem.

Thanks,

Jason.