Lighting fault

GalaxyMark

I am a very competent DIYer and have a problem with my lighting upstairs. The fuse blows after about 10 minutes and have been trying to track down the fault with little success. Any ideas appreciated.

Thanks

sevenhills

When I had my boiler fitted, they screwed into a lighting wire. Any new DIY jobs recently undertaken?

GalaxyMark

Thanks for the response - nothing recently but not ruling anything out been trying to trace the wiring from the loft down and not found anything obvious yet.

tacpot12

Is it a fuse or Miniature Circuit Breaker (MCB) or RCBO that is blowing?

The fact it takes 10 minutes to blow suggests that the device is operating correctly to prevent excess current from damaging the cable. The problem could be high resistance at a junction box or light fitting caused by a loose connection or it could be due to cable damage allowing a current to flow from the live to neutral cables. if there has been no recent DIY work, a loose connection sounds the more probably. if you have an ohm meter and a long enough wander lead cable, you can check the resistance of the line and neutral conductors between the fuse box and the furthest point on the lighting circuit, to see if there is any difference between the resistance of the two conductors. Remember to isolate the circuit and check that it is isolated.

I would get an electrician in as they will know how to find the problem much more quickly and with less risk.

GalaxyMark

It's a fuse. The old style fuse box with fuse wire.

Thanks for the advice. The time it takes for it to blow does change sometimes only a minute but can be much longer.