First post so please be gentle. I am no sparks but am ok with basic wiring.
Looked through forum but can't find exact problem we have.
Have a 6 amp MCB in the CU feeding 2 lighting circuits - kitchen and utility room. The MCB trips after 10 minutes or so. Until then all lights work fine. It will trip even if all the lights are switched off.
MCB can be reset but trips again after 10 minutes. If you keep resetting it, the time taken to trip is reduced gradually.
I have isolated the problem to the utility circuit by removing its connection to the MCB. The kitchen circuit then works fine, no tripping. So the tripping is caused by the utility room circuit.
On the utility circuit are four interior 60 watt incandescents, and three outside lights. I thought it may be a problem with the oldish outside lights so I have removed the fittings and (carefully) taped up the wire ends. No change - it still trips.
I am confused why there is such a delay before tripping. I guess some kind of short would cause it but why the delay? Is it likely to be some sort of earth leakage caused by damaged wiring? What can I do to fault-find this? I have a good multimeter.
It has been like this for some time (years!) as I disconnected the utility room and we have been using a table lamp in there. Now I have received orders to sort it out or no more clean clothes....
Please help!
Looked through forum but can't find exact problem we have.
Have a 6 amp MCB in the CU feeding 2 lighting circuits - kitchen and utility room. The MCB trips after 10 minutes or so. Until then all lights work fine. It will trip even if all the lights are switched off.
MCB can be reset but trips again after 10 minutes. If you keep resetting it, the time taken to trip is reduced gradually.
I have isolated the problem to the utility circuit by removing its connection to the MCB. The kitchen circuit then works fine, no tripping. So the tripping is caused by the utility room circuit.
On the utility circuit are four interior 60 watt incandescents, and three outside lights. I thought it may be a problem with the oldish outside lights so I have removed the fittings and (carefully) taped up the wire ends. No change - it still trips.
I am confused why there is such a delay before tripping. I guess some kind of short would cause it but why the delay? Is it likely to be some sort of earth leakage caused by damaged wiring? What can I do to fault-find this? I have a good multimeter.
It has been like this for some time (years!) as I disconnected the utility room and we have been using a table lamp in there. Now I have received orders to sort it out or no more clean clothes....
Please help!