DIY Doctor UK DIY Forums

Hi all, very wierd problem here that I am trying to sort out myself if I can.

started last week when I switched a light on downstairs and it didnt come on for 30 seconds. This happened on all downstairs lights. then after a couple of days the lights would not come on at all. The house was built in 1991 and has a trip switch which goes off if a bulb blows but this had not tripped.

I have had all the light switches off to see if a wire had come loose but cant see one. Someone suggested I tried to take the fuse out of the box and swop it with the upstairs which is working fine. Have taken cover off fuse box but no way can i work out how to get the fuse out as it appears to be fixed.

Any ideas on what the problem may be? apart from this have not had any problems. I did notice that in toilet about month ago i fitted one of those energy efficient bulbs and when i switched that on it took about 30 seconds to come on but I just assumed it was a different type of bulb ut maybe its a problem there.

hi, given the age of the wiring it is unlikely you have fuses, most probably MCB's which are permanently connected to the fuse boards live busbar.

Could you have disturbed a connection in the bathroom ceiling light?

supply usually loops from light to light not switch to switch, so it could be the first one in line from your consumer unit thus affecting all the rest.

Take great care at consumer unit, turn off main switch before removing cover as if you accidently short across the mains tails several thousand amps can flow before supply fuse blows!!!
regards Sparx

The MCB (Miniature circuit breaker) is designed so if there is a fault you can't force it into on mode. As a result it can have the lever in on position when in fact it is off.

I would turn power off at main switch. Then switch the MCB off and wait for a few minutes to ensure it is cool then turn MCB back on. Then turn power back on. If there is a fault you will then see the lever on the MCB move to off position and if no fault you should see it remain on.

To those of us who use MCB's we can normally feel the difference between tripping as we switch it on and really going to on position. If you compare action of faulty switch with good one you may also feel the different action.

They can also become faulty themselves but I would be very wary of trying to change yourself as likely if it is faulty it has got that way because of a fault so would be prudent to call an electrician so it can be tested.

thanks both for your replies. I am not confident enough in dealing with the electrical side of things especially as we are taking about the main fuse board so think I will have to get someone in to take a look.