Hi people!
Right just done a CU swap, tested all circuits and ok, did the IR L-E, N-E on the upstairs lights and got the reading of 0.29MOhms and 0.24.
Have got no idea on where to start looking for faults or disconnecting? Should i be taking bulbs out? transformers for downlighters in bathroom? Pretty sure its all ok as RCD is fine and house is 15 years old so not old wiring.
tester is ok as used for all other circuits.
Need some help please people!!!!!!!!!! ASAP!
Jason
Yes you must remove lamps, dimmer, not test throu RCD etc, retest, once you done this, if still low, inspect flex between ceiling rose and lamp holder.
As for fault finding the 50/50 method is the best, first remove neutral, earth and switch breaker off for line, then roughly divide the circuit up 50/50 at that oultlet split the line neutral and earth and test each half this should eliminate 50% of the circuit from fault finding. if one half give you a low reading subdivide that half again, and so on.
I do suspect over heating or insulation damage (loose connection) could be cause of you low insulation, so as previously stated check all lampholder also in vestigate if ther could be a junction box or similar joint in the ceiling.
May be check termination entering board, have had experience where insulation has been damaged by metal enclosure or knife cutting throu insulation showing bare copper, then moisture damp shorting out conductors or it could just be because of the age of the wiring, inspect it all, I had person connect PVC to VIR etc.
Personnelly I alway perform PIR inspection and test of the electrical installation before any board changes, yes it add time and cost to the board change, but it save me a lot of hassle and addition cost in the long run.
You could be in a position where the lights needing rewiring and a client unwilling to pay for it, and do not leave it as you changed the board and have to issue test cert with you name on etc, it could work out very expensive if sued/prosecuted, I hope not.
Best of luck and let us know how you get on.
