Upstairs lights out

Posted 16th Mar
Hi upstairs lights out. MCB 6a mem breaker keeps tripping (even after removing all light bulbs / isolating wall switches) still immediately trips as soon as put it on position.

Someone said I need to find the fault using a multimeter by checking each Ceiling / wall connection.

Any tips on how to do this and recommendations of which is most suitable multimeter

Many thanks in advance... it's not the Corona that will kill me ... it's my other half constantly going on
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Try swapping the breaker around, it could have failed!
Esar ... tried it No joy
Sounds like a wiring fault then. I wouldn't recommend fault finding mains stuff if you don't know what you're doing, best call in a professional.

If you have pendant light fittings, you could always unscrew the ceiling rose and look for something obviously wrong (with the power off) but I wouldn't go any further than that.
Thanks freakstyler
Prob need an insulation tester. If it was me I would do as above first...remove all light switches (ensure power off) and ceiling roses to check for loose or damaged wiring (include downstairs or elsewhere if on a multi way switch). Any home works been done recently...nail through wiring (dont touch anything if power live). At that point I would then ring for the pros...not worth tampering and a fault such as this could result in fire. Good luck
Do you have an outdoor floodlight, or a shaver socket connected to that lighting circuit, as those would be my first suspicion, unless you have a period house that still has rubber insulated cables.

Light circuits are usually connected in a chain, with the power feed for the second light connected at the ceiling rose of the first, etc.

So, if you have ceiling roses, and are suitably competent person, you may be able to break the lighting circuit by disconnecting at least two of the three wires at the loop in terminal (marked "live terminal" in the image) after turning the power fully off first. Don't rely on the MCB in case you also have a dead bulb on one of the still live fittings.


Once disconnected you can test the wires in each cable for a short, and repeat at the next ceiling rose to narrow the fault down.

Disclaimer, I am not an electrician, and if you are not 100% certain what you are doing is safe, you need to call one out.
Edited by: "melted" 16th Mar
Is the light on a 2 switch circuit like a landing light? I had one that tripped as soon as used after some rewiring was done. It was diagnosed as some sort of earth loop and the solution was to take the earth from another junction in the loft.
sounds like a neutral leak. need to disconnect each fixture, start with the first in the loop gradually moving to the last. also worth checking the switch first. disconnect it completely and see if your breaker trips, that way you know if it is the line before or after the switch.
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