I wonder if anyone has ever come across wiring like this, which basically consists of a copper rod in the wall/ceiling, then capped with a brass cap and some black goo at the point where it is to be connected to socket/switch/rose. This is in a flat built in 1972 with shuttered concrete walls.
I was replacing a light switch when suddenly the wire broke off from the brass cap and I am left with only one wire to my switch! Need to find a way to fix this, hopefully without running a new switch cable - mainly because it is complicated enough as it is.
At the rose end, where I have disconnected the switch wire, I have no clue which is live/neutral/earth and only one wire is live (as tested with a voltfinder once power was re-applied). Most wires are sheathed with black or green insulation, but I am pretty sure most of the green ones aren't earth!
Thanks for your help,