problem with lighting

ooter

i have a problem with 3 of the downstairs lights in the house,when i switch 1/all of them on they might stay on for only 3 mins or sometimes as long as 30 mins but eventually they go off and 1 of the switches on the fuse box goes down.if i flick the switch back up and turn the light(s) back on the same thing happens again.

anyone know what the problem might be and if i'd be able to fix it meself?

M cebee

prob a short-circuit -is it a mcb ? (or an rcbo for outside even)

dampness,fluorescent ballast or something

is it a 3-gang switch-do you know which light is giving the trouble

Bruthal

Sounds like a short alright, any outside lights on the circuit?
Last time i seen similar it was actually the bath upstairs leaking onto the kitchen light fitting below.

Could be a wire in switch with damaged insulation shorting onto metal back box if there are metal ones behind switches, or a problem at one of the light fittings themselves.

But you probably need to get someone to go looking at the affected switches/lights, them problems can be tricky to find at times.

Try each light on its own in turn for a while, turn it off and the next one on, so you might narrow the problem down to one light.

Also can you tell us if its a normal MCB or rcbo/rcd thats tripping. Take a photo and show us.

ooter

Thanks for the replies lads.
It's actually my sister's house,she sent me a txt on Friday so I thought I'd post it on here cos I wouldn't be too clued up when it comes to electrics.
I just rang her and she said 1 of the lights in the kitchen (there's 2),1 of the lights in the living room (there's 2) and the downstairs toilet light are the ones acting up.I wouldn't know off the top of my head what kind of circuit board it is ,i'll try and call over later and get photos.
She also mentioned hearing a buzzing sound when the lights go and it sounds like its coming from the back garden,don't know if that's related..

Bruthal

Usually buzzing is caused by a bad connection or dampness in a light, but it would not be espected after the MCB has tripped.

ooter

Just back from the house,it looks like the problem is definitely coming from wires out the back.I had a look out there and there's a plastic box on the wall with 2 wires inside,I assume that's for a light to be fitted.
Anyway the box wasn't fully closed and when I opened it the box was black in one corner and one of the wires was black.I closed the box as best I could and told her to let me know if the lights go back off,haven't heared anything back from her yet.I have a couple of photos on my phone,i'll try an upload them later if I'm near a computer.
She said it's been happening since last Wednesday so I can only assume that the bad storm caused some damage.
Will this eventually fix itself or will the wire continue to cause problems now that it's black?
Is there any type of waterproof tape I can get to cover the wires/box with?

Bruthal

ooter wrote: »

Just back from the house,it looks like the problem is definitely coming from wires out the back.I had a look out there and there's a plastic box on the wall with 2 wires inside,I assume that's for a light to be fitted.
Anyway the box wasn't fully closed and when I opened it the box was black in one corner and one of the wires was black.I closed the box as best I could and told her to let me know if the lights go back off,haven't heared anything back from her yet.I have a couple of photos on my phone,i'll try an upload them later if I'm near a computer.
She said it's been happening since last Wednesday so I can only assume that the bad storm caused some damage.
Will this eventually fix itself or will the wire continue to cause problems now that it's black?
Is there any type of waterproof tape I can get to cover the wires/box with?

The best to do is put the cable into a proper waterproof box and connectors on the ends of the cable, dont tape the connectors as i think that only traps moisture in the connectors if any gets in. Bring the cable up into the bottom of the box if you can stick the box to the wall.

It seems simple to do but it would be easier for a sparks to sort it.
Is there no switch inside for turning the outside light off, when there was a light fitted?

M cebee

sounds like your problem

but you'll need to get someone competent to fix it

ooter

The thing is,the house is 3-4 yrs old and that box and wires has always been out the back so I'm surprised its only causing problems now..

ooter

the middle switch in the bottom pic of 3 is the one that keeps tripping

Bruthal

Lookin at them pics of the box outside i can see the problem, the cable is clean cut but not stripped so the Live and Neutral cores are very close together in the end of the cut cable while its live, so any moisture that got in when the lid was not on properly could easily cause burning at first then a short as the current tracking in the moisture burns the end of the cable carbonizing it and shorting, tripping the breaker.

The cable needs to be de-energised first, then an inch or 2 cut off it, a couple of inches of outer insulation stripped and the cores terminated into connectors. All of this in a weather proof box, the box it was in might be ok. Dry inside it as well. And make sure the box is fixed in such a way that the cable is into the bottom of it so rain cant go in where cable goes in.

I would of thought there should be a switch inside to turn the cable off when there is no light fitted?

Over all a sparks should be got to look at it anyway.

Bruthal

ooter wrote: »

The thing is,the house is 3-4 yrs old and that box and wires has always been out the back so I'm surprised its only causing problems now..

Maybe the box was sealed up until recently. I actually had the same oboe box on the end of the cable on my house for fitting a light over back door. Was there about 5 years (new house) before i eventually fitted the light. But if any moisture gets in they will cause problems. A connector should of been fitted to end of that cable from the start though. As i said, with just a clean cut cable, the ends of the cores are very close together so will sizzle away if any dampness gets on end of the cable.

If that was on the house from start there should be a switch to turn power off to that cable/box outside and left off when no light is fitted.

ooter

Thanks a lot for the replies lads,this has been a really great help.
Don't know why I didn't think of checking for a switch inside,I'll go back over and do that this evening.haven't rang my sister yet but I did tell her to let me know if the lights went back off and I haven't heared from her since..

M cebee

don't get the original guy back anyhow:)he must be clueless

that box should have a screw-on lid and connectors and probably rcd protection required

a hazard when kids are around

Bruthal

Yes ireland seems to have 2 sets of imbasils and no doubt more, drivers and sparks.

ooter

if there is indeed a switch in the kitchen and she turns it off will that solve the problem or will she be as well to get a sparks out anyway and safeguard that wire/box out the back?
it's pretty high up on the wall so i can't see the kids going anywhere near it...

Bruthal

ooter wrote: »

if there is indeed a switch in the kitchen and she turns it off will that solve the problem or will she be as well to get a sparks out anyway and safeguard that wire/box out the back?
it's pretty high up on the wall so i can't see the kids going anywhere near it...

If there was a switch it would be a good idea to disconnect the switch wire from it and put a connector on it, this is the wire from the switch to the outside box. It needs someone competent at electrical work to do this really, simple as it is for a sparks. This would then leave the outside setup safe.

But i would still weatherproof the outside box as the cable may be used sometime and its not a good idea to leave it to the elements.