Problem with upstairs lights

[ktartandude]

Hi. A light bulb blew with a loud pop in an upstairs bedroom and knocked all the other upstairs lights out with it. Naturally I presumed it had blown a fuse. The fuse box is the old rewirable fuse type and has a 5amp, 15amp and 2x 30 amp fuses. All the fuses are intact and whatsmore none of them seem to be connected to the lights.
First question: is it possible for the lights to be run of the mains without a fuse???
Second question: If this isn't a fuse problem, any ideas on what the problem may be?
I should also add that the controller for the central heating died at the same time and I assume this must be linked in to the same circuit and therefore may be related. Maybe not.
Thanks for reading and I appreciate any help.

 

[Adam_151]

Chances are it is a fuse, but you just can't find it

Have you got many different fuseboxes or just the one?

Pull fuses and find out what stops working, you should be looking for a 5A fuse and the one in the fusebox might be the downstairs lights,

Also look for an FCU, looks like a socket, but instead of 3 sqaure holes has a fuse drawer that takes a plug fuse, I suppose something like this could be just about anywhere

Its also possible that you have a single lighting circuit and the fault current has blown apart a very loose connection (if thats the case then its done you a favour because loose connections can and do start fires)

 

[ktartandude]

Thanks Adam.
The 5amp in the fusebox controls one light in the house, the one in the cupboard where the fusebox is strangely enough. The other lights, even the downstairs ones are not affected even on pulling all four fuses.
I cannot find another fusebox in the house and have been searching for an FCU with no luck.
I assume that you're saying that there must be a fuse for it somewhere and that it couldn't run off the electrics directly. I'm saying couldn't and not shouldn't since the previous homeowner was a DIY madman and I'm not sure how much of his work is entirely professional

 

[Steve]

you couldn't put up a picture of the mains intake could you? And the meter and main fuse if possible?

(If you feel really confident, take the cover off the fusebox and show us its innards - this would be a great help, but please turn everything off and only do it if you're confident to do it - the meter tails inside the unit are still live)

 

[ktartandude]

Sorry. I don't have a digital camera. What would you be looking for exactly? You think there may be a problem in the fusebox?

 

[Steve]

Sorry. I don't have a digital camera. What would you be looking for exactly? You think there may be a problem in the fusebox?

Well, there are 2 possibilities . . . .

1. The lights are wired into the top of the main switch, with the meter tails. INCREDIBLY stupid thing to do. The top of the main switch (on the right IIRC) should have only 2 wires - the 2 large meter tails.

2. There is another fusebox somewhere. Look at your electric meter. Where the 2 tails come out, do they go straight into the fusebox? Or is there a couple of boxes where the tails split, and one pair goes off somewhere to another fusebox?

 

[plugwash]

does turning off the main switch in the CU kill the downstairs lights?

are the service fuse seals present and intact?

 

[Adam_151]

If none of the fuses in the fusebox cut power to the lights then the the power to the lights must somehow branch off before the fuseways, there are legitimate ways of doing that (by taking the main cables 'tails' into a service connector block to split them and having two fuseboxes) its also possible that DIY Disaster Dave might have thought to bodge them directly into the supply tails somehow.

As others have said, switch the fusebox isolator off to see if that cuts the light power to find out which side of the switch it comes from, if it doesn't power down the lights then look to see if the tails between the meter and the CU branch in service connector blocks, or if the meter has two sets of outgoing tails, etc

if you find nothing then open the CU very very carefuly (with switch off - but aware that at least the incomming tails will still be live, and god knows what in this install)

If the main switch cut the lights, look at the bars/cables between the switch and the fuseway for extra wires, if not, then look at the imcomming side of the switch (remember this will definitely be live)

If you could borrow a digital camara, a pic would make things so much easier

 

[ktartandude]

Fantastic response. Thanks guys.

There are further cables which led into a side panel and ... another fuse box. In building out the cupboard this box has been boarded over. Not any more though

Fuse found, fuse wire replaced, problem solved. Thanks again for the help.