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[louwood55]

Hi, I have aproblem with fitting ceiling lights. I have a room with 2 different lights in the ceiling. The first light was changed and all was well, they both worked fine, switching on and off with the light switch. I then came to change the second set and there was 4 wires coming from the ceiling. I have wired them up using the loop system and have my tagged live switch attached to the live of the light and the neutrals to neutral and earthed the earth. The problem i have is now when i turn the fuse back on the original light fitting, which has just 1 wire with 3 wires is on permanently and the second tagged fitting works on the light switch. can anyone offer any advise as to what is causing this. I have tried checking in the loft for which wires are which but its like the house jack built.
thank you

[ericmark]

With the second light one of the four cables should feed to first lamp so one of the wires in the “Loop” terminal should have been paired with the tagged live switch wire.
Most likely way to find out which of the wires in loop is wrong is to temporary disconnect one at a time.
a) Nothing works including other lamps in house past this point this would be feed and should be in loop.
b) Neither the lamps in this room work this would be switch feed and should also be in the loop.
c) Lamps in some other rooms stop working this would be feed to rest of house and again should be in loop.
d) First lamp only does not work this is wire you are looking for and should go with tagged live switch wire and not the loop.
Do be careful of course I would use a terminal block or insulation around the wire being tested to stop it touching anything while under test and of course isolate at mains between each test.