by kbrownie »
Fri Jun 09, 2017 6:39 pm
It would be strange just to have grey, black and CPC (aka earth) at the fitting, as these colours are normally associated to a three core and earth cable. So there should be a brown core present.
With regards to what the cores are acting as, would be impossible to say, as the original installer, could have wired it differently to the conventional way. I would have expected the cores to be sleeved to at least identify them.
Only by testing the cores, would it be possibly to establish what purpose they serve. So you require a multi-meter and once established, I would recommend sleeving the cables to ID them,