Help! Electrical

[Caledonian]

Hi all, I'm looking for ideas/suggestions

Came home last night and no lights in bedroom or bathroom.
Thought it would be a bulb so reset the trip, going to change the offending bulb.
But trip clicked down again immediately
So went to bed and decided to look this morning again.

Have taken all the bulbs out on that circuit and pulled the fuse from extractor fan, not sure if it's on same but may be.
Still as soon as you lift the trip it clicks down again???
My good lady informs me that it did same a couple of times a week ago but never since.

I don't know where to look next, any ideas out there?

Jack

Edit: I should have said there has been nothing added to the system, no new lights, switches or rewiring.

 

[normspanners]

Is it the rcd trip or the breaker that is tripping?

 

[Caledonian]

'Morning Norm
The little one on the strip of switches, it's marked as 6 amp
Situation just got worse! It also controls lights in my garage lol

Jack

 

[cumbriasteve]

Had a similar issue, it was a light switch, when I removed it there was signs of burnt terminals, sort of dark brown burnt appearance around one of the wire entry points.

A new switch and sorted.

 

[Caledonian]

Thanks Steve, I'll carry on checking the switches and roses
Oh the joys, this was gonna be a welding day

Jack

 

[madkayaker]

my first guess would be outside lights? or switch or cable damage

 

[wheresmejumper]

or faulty mcb

 

[Wedg1e]

Has it rained much? I'm thinking water in the garage wiring...

 

[madkayaker]

unlikely. have only ever come across 1 in 10 years of sparking

 

[Caledonian]

Thanks for all the responses guys

Outside lights are on another circuit and are fine.
I thought I had it following Steve's post.
Checked all the switches and then ceiling roses, only lights at one end of house are affected.
Terminals on one of the roses looked burnt, brittle and blackened. I cut wires back to clean after junking the rose and tried again, failure, still tripping
Hell's Bells, next 2 roses were worse! all 3 are deep roses with a thread for a glass globe. Removed them, cut wire back to clean and tried again still tripping!
Faulty MCB? Could the continual tripping damage it? How would I know? Have to get another and try it? Where would I get one on a Sunday?

Jack

 

[madkayaker]

MCB's can trip thousands of time at well above currents likely to be reached in a house. Do the cables run through loft and has something been placed on cables?

to check MCB isn't faulty remove the outgoing in the fuse board and try turing it back on also check for burning on cable in there

 

[Caledonian]

Cables do run through the loft but not been up there for months.
Silly question but it is OK to check MCB with nothing on the end of the wires? I mean the roses are off now and wires are just hanging there spread like a gymnast's legs

Jack

 

[normspanners]

Try disconnecting the feed to the garage lights.

 

[piman]

Hello Jack,

disconnect the out going wire(s) from the mcb, if it stays in you still have a fault somewhere. If there is more than one wire connected to the mcb, reconnect one by one until it trips again, then you have a clue as to which area you need to look at.

"Silly question but it is OK to check MCB with nothing on the end of the wires?"

Yes, simply put an mcb is a switch with a mechanism sensitive to the current drawn, if it's too much the mechanism inside opens the switch. No current at all will not affect it.

Alec

 

[madkayaker]

Cables do run through the loft but not been up there for months.
Silly question but it is OK to check MCB with nothing on the end of the wires? I mean the roses are off now and wires are just hanging there spread like a gymnast's legs

Jack

not ideal as the ends will be live but as long as no one can touch not the end of the world.

sounds like you need a sparky as from here your into testing cables for faults. if oldish house or one with rodent problems chewed cables are common fault

 

[wheresmejumper]

have replaced at least 20-30 faulty mcb's
you should reconnect those wires hanging down,or at least the neutrals,or you wont be testing the whole circuit.
possibly a loose connection somewhere along the line

 

[Caledonian]

Getting somewhere now but just not sure where
There were 2 wires coming out of the top of the MCB, I disconnected one and hey presto I've got lights in the garage again
So obviously the other wire feeds the lights in bedroom, bathroom and hall.
As far as I remember the only exposed cabling in the loft goes to the garage.
Would it be worth disconnecting all the switches, same as ceiling roses?
My first instinct, now that lights are on in garage, is to go do some practice welds as planned for today but somehow I don't think I'll get away with that

Jack

 

[wheresmejumper]

check for moisture in any bathroom fitting

 

[cumbriasteve]

If the fault is a switch or rose then cutting back the wires won't help, you really need a new switch and rose and keep changing as you go along, replacing the original as you go along if the fault is not cured..

Could be anything the others have mentioned of course but if I had to bet a tenner it would be on a switch or rose shorting out.

Edit: Was not thinking..simply removing the wires from switch and trying system will tell if it's that one... the bare wires will of course be live so great care required that no one can approach them during the test period.

 

[shed or dead]

As a 'think outside the box' consideration, have any pictures been hung on walls recently? I once heard of a screw penetrating through cables behind plaster in an old house. The tripping rcd didn't manifest for a few weeks until the picture had been knocked.

If this could be the case, remember to isolate power before tackling any potentially offending screws / nails.