find the fault

[Guest111]

Hers a little scenario to test fault finding skills,let some of the new guys have a go first.

Fitting a polycarb light in a corridor,guy says there is a cable in the void above that is live.IT'S a thin grey cable in a jb one leg is red and the other has black sleeve over it,there is no earth.connect up light fitting class 2 so why worry about lack of earth? power up switch on and rcd trips.single rcd covering all circuits,IR test fine circuit was ok till light fitted and now this problem.question is what is it?
This is from something I found on a job in a house years ago,over to you chaps

 

[DPG]

The thin grey cable is a phase and earth, but the earth has black sleeving over it? Daz

 

[Deleted member 72666]

Daz beat me to it!

 

[Tridentsystems]

Maybe some testing before connecting ? Unless you believe customers !!

 

[Tridentsystems]

Maybe I have assumed guy was a customer ?

 

[Guest111]

Correct! the guy had bought an ex council house which was wired in singles,for some reason this switch wire had been left in the ceiling and was fed from a 2 gang switch,seeing int was a 2 core the guy thought it would be handy for a new light in the corridor and had fitted a plastic drum type fitting,connecting a piece of T+E from the fitting to the jb.If he'd have stripped the original "twin" back he'd have discovered as Daz correctly picked up that it was a single and earth.well done chaps,proves there's still some sparks on here.