Omega Owners Forum
Chat Area => General Discussion Area => Topic started by: Taxi_Driver on 14 February 2012, 19:03:38
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What could be causing an intermittent Neutral to Earth fault that makes the main trip in the fuse board to go??
I've discovered its on the downstairs lighting circuit......sometimes its weeks, but for last few days its been everyday the main trip has gone.....sometimes the main breaker will turn back on fine, other times i have to turn off the downstairs lighting circuit to get the main trip to stay on.
The reason i reckon its an N/E fault as the trip will go even if all the downstairs lights are off.
I did wonder if it could be a low energy bulb doing it......theres 5 on the circuit :-\
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What kind of breaker is it throwing - RCD/RCBO/etc or MCB?
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Some are wired with switched live, some switched neutral. So could be Live.
Is it the earth leakage trip that fires, or a circuit specific, or the main 100A one?
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Some are wired with switched live, some switched neutral. So could be Live.
Is it the earth leakage trip that fires, or a circuit specific, or the main 100A one?
Its the main 80A one, which i assume has earth leakage builtin, as i dont have a seperate earth leakage breaker. The 5amp breaker for the lighting circuit doesnt trip.
Its says on it RCO circuit breaker. Max current 80Amps 30ma trip.
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Any strip lights on the circuit ?
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Has your consumer unit just got the one combined rcd / main switch or is it a split load unit ?
What makes you think its the lighting circuit ?
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Any strip lights on the circuit ?
Nope, only 5 low energy bulbs, which i did wonder about.. :-\
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Is it tripping when you switch something on or does it trip when it feels like it ?
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Sorry, just read all the post :-[
Doing about 10 different things at once at the moment ::)
I'd swap the energy saving bulbs for normal bulbs for starters.
Bear in mind that if you only have a combined rcd / main switch, you consumer unit will have a common busbar for the neutral so the fault could be on any circuit.
Kettles and fridge / freezer compresors are a favorite :y
Also bear in mind that just switching the 13 amp socket off doesn't always totally isolate the appliance.
Most sockets just switch the live leaving the neutral and earth conected :y
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Kettles and fridge / freezer compresors are a favorite :y
dishwashers ::)
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Has your consumer unit just got the one combined rcd / main switch or is it a split load unit ?
What makes you think its the lighting circuit ?
Sometimes the main breaker wont turn back on.....turn off this circuit and it will...
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Sorry, just read all the post :-[
Doing about 10 different things at once at the moment ::)
I'd swap the energy saving bulbs for normal bulbs for starters.
Bear in mind that if you only have a combined rcd / main switch, you consumer unit will have a common busbar for the neutral so the fault could be on any circuit.
Kettles and fridge / freezer compresors are a favorite :y
Also bear in mind that just switching the 13 amp socket off doesn't always totally isolate the appliance.
Most sockets just switch the live leaving the neutral and earth conected :y
Done that now......still doing it.....seems to be getting worse....tripping about every 15mins now :(
Think i'll have to get an electrician in.....
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I reckon you've got some damp in the circuit somewhere, i.e. bathroom plumbing leaking into a downstairs ceiling rose?
However, as said, it might be that there are other faults on other circuits that are all contributing to the leakage and it just happens to drop below the 30mA trip if you isolate this circuit.
Only real way to narrow it down would be to disconnect the circuits one by one at the consumer unit and megger the live and neutral against earth to see if you can spot where the worst of the leakage is.
EDIT: By disconnect above I mean remove both live and neutral connections at both ends of the ring.
Low energy bulbs don't normally have any earth connection (the whole bayonet connector is usually plastic).
Any outside lights on that circuit (paranoia lights. etc)?
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As Kevin said :y
Also have you replaced any light fittings recently ?
What circuit is tripping ?
Up or down ?
If your handy with a screwdriver, and know the approx route of the cables. You could try and split the circuit up by picking a light fitting half way round. TURN OFF THE CIRCUIT and remove the live and neutral wires out of the fitting the power it back up :y
If it trips again, do the same and work your way back to the consumer unit. If the circuit holds, TURN OFF THE CIRCUIT and disconect the wiring further up until you isolate the part of the circuit that is tripping ;)
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Any strip lights on the circuit ?
Nope, only 5 low energy bulbs, which i did wonder about.. :-\
It's not uncommon for CFL's to cause nuisance tripping, especially if they are the cheap crap that you find on the supermarket shelves.
As it's tripping so often, fault finding should be relatively quick.
Start by removing ALL the CFL's from the lampholders on the circuit you believe to be at fault and wait. If the RCD still trips then I'd be thinking along the same lines as Kevin in that a bit of damp has found it's way in to a ceiling rose, which means that visual inspection is the diagnostic tool of choice.
If the RCD stays in after you have removed the CFL's, that means one of them has gone a bit leaky and the only way to diagnose the culprit will be to reinstate them one by one until the fault reappears.
There is also the possibility that the RCD itself has gone a bit weak (I've had that happen on a brand new CU that was less than 2 weeks old), in which case replacement is the only cure.
Please note that while replacement of the main switch/RCD is fairly straightforward, it is a job for a QUALIFIED sparks only.
I say that not so much because of the Part P 'dangle berries', but mainly because you have no safe way of isolating the meter tails.
If you were to make a mistake while working in that area of the CU, then it would more than likely be your last as there is 100A sitting on the end of those tails and the only fuse in that scenario will be you (and you would fail at around 125mA).
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I had a faulty RCD a couple of years ago. It had always been over-sensitive IMO but when it finally gave up it simply wouldn't hold in the on position at all!
Must admit that I replaced it myself because it was 9pm and we needed the power back on, but I was well aware (and very careful!) that there was nothing isolating the meter tails ::) SWMBO was having a right old panic, but I just did it using a bit of the old common sense ::) Don't touch any metal! ;D
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If you were to make a mistake while working in that area of the CU, then it would more than likely be your last as there is 100A sitting on the end of those tails and the only fuse in that scenario will be you (and you would fail at around 125mA).
And then some in a fault condition if you let them touch. :o
Whilst I'm quite comfortable working on most electrical stuff including, in the past, valve transmitters with 3kV of DC on the anode while sitting in a damp tent on top of a hill, I'd draw the line at replacing one of these live.
Faced with a similar predicament a few years ago (Wood and bakelite consumer unit that literally fell part in my hands as I was taking the cover off) I had no hesitation in cutting the seal and pulling the fuse out of the incomer.
I phoned up the leccy board and confessed and they didn't bat an eyelid. The seal was renewed at the next meter change a few years later without comment.
I'd probably be hung, drawn and quartered these days, of course. ;D
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If you were to make a mistake while working in that area of the CU, then it would more than likely be your last as there is 100A sitting on the end of those tails and the only fuse in that scenario will be you (and you would fail at around 125mA).
And then some in a fault condition if you let them touch. :o
Whilst I'm quite comfortable working on most electrical stuff including, in the past, valve transmitters with 3kV of DC on the anode while sitting in a damp tent on top of a hill, I'd draw the line at replacing one of these live.
Faced with a similar predicament a few years ago (Wood and bakelite consumer unit that literally fell part in my hands as I was taking the cover off) I had no hesitation in cutting the seal and pulling the fuse out of the incomer.
I phoned up the leccy board and confessed and they didn't bat an eyelid. The seal was renewed at the next meter change a few years later without comment.
I'd probably be hung, drawn and quartered these days, of course. ;D
Not if your friendly electric board man gives you a bag of lead seals you don't :-X ;D
As for the fault, start with the simple things first :y
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I had a faulty RCD a couple of years ago. It had always been over-sensitive IMO but when it finally gave up it simply wouldn't hold in the on position at all!
Must admit that I replaced it myself because it was 9pm and we needed the power back on, but I was well aware (and very careful!) that there was nothing isolating the meter tails ::) SWMBO was having a right old panic, but I just did it using a bit of the old common sense ::) Don't touch any metal! ;D
That reminds me of an incident a couple of years ago when the other half watched me make a screwdriver completely disappear.
My partner in crime & I were on site in Farnham one day when the missus and her mate arrived to borrow the 4x4 so they could do whatever it was they were doing. I was connecting a lift to the 3 phase supply while it was still live (we couldn't kill the juice for various reasons) and I let my attention (plus the screwdriver I was holding) slip for a moment when the missus was asking me for the keys.
The uninsulated screwdriver I had chosen to use ended up shorting across 2 busbars, which resulted in an almighty bang accompanied with a flash of blinding light and a shed load of sparks as 200A @ 415V passed through the screwdriver blade.
While it certainly gave me a quick shot of fright, it made the missus (and her mate) properly crap themselves when it happened as they were only a few feet away ;D
The flash of light was so intense that everything I looked at for the next hour or so afterwards had that "Ready Brek" orange glow around it, and the only part of the screwdriver that could be found was the handle (at least it sort of looked like the handle).
The actual metal part of the screwdriver had been completely obliterated, save for the few small bits that were now welded to the busbars when the screwdriver first made contact.
My first mistake was using an uninsulated screwdriver, and my second mistake was allowing myself to be distracted with my pinkies inside a live board. As fortune would have it I was wearing rubber soled boots and stood on a fibreglass ladder at the time, if I hadn't then I suspect the outcome would have been quite different because 3 phase doesn't give you a chance like domestic 230 does.
Anyway, I digress.......the reason I put the word qualified in block caps is because I was unsure of your ability/confidence in playing with electricity.....and a simple oversight could quite easily result in early demise.
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Faced with a similar predicament a few years ago (Wood and bakelite consumer unit that literally fell part in my hands as I was taking the cover off) I had no hesitation in cutting the seal and pulling the fuse out of the incomer.
I phoned up the leccy board and confessed and they didn't bat an eyelid. The seal was renewed at the next meter change a few years later without comment.
I'd probably be hung, drawn and quartered these days, of course. ;D
Unbelievable as it sounds (for these days), the leccy board still don't raise an eyebrow when you phone them up and ask for a reseal because they know it is the ONLY way you can isolate the incoming supply in order to work on the meter tail side.
These days I tend to break the seal on the meter and drop the tails from there (always using an insulated screwdriver after my lesson at Farnham ;D) as it's reasonably safe providing you don't take your eye off the ball. That method also removes the worry of someone sticking their pinkies in to the fuse carrier which has a live terminal exposed when the fuse is removed.
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I had a faulty RCD a couple of years ago. It had always been over-sensitive IMO but when it finally gave up it simply wouldn't hold in the on position at all!
Must admit that I replaced it myself because it was 9pm and we needed the power back on, but I was well aware (and very careful!) that there was nothing isolating the meter tails ::) SWMBO was having a right old panic, but I just did it using a bit of the old common sense ::) Don't touch any metal! ;D
That reminds me of an incident a couple of years ago when the other half watched me make a screwdriver completely disappear.
My partner in crime & I were on site in Farnham one day when the missus and her mate arrived to borrow the 4x4 so they could do whatever it was they were doing. I was connecting a lift to the 3 phase supply while it was still live (we couldn't kill the juice for various reasons) and I let my attention (plus the screwdriver I was holding) slip for a moment when the missus was asking me for the keys.
The uninsulated screwdriver I had chosen to use ended up shorting across 2 busbars, which resulted in an almighty bang accompanied with a flash of blinding light and a shed load of sparks as 200A @ 415V passed through the screwdriver blade.
While it certainly gave me a quick shot of fright, it made the missus (and her mate) properly crap themselves when it happened as they were only a few feet away ;D
The flash of light was so intense that everything I looked at for the next hour or so afterwards had that "Ready Brek" orange glow around it, and the only part of the screwdriver that could be found was the handle (at least it sort of looked like the handle).
The actual metal part of the screwdriver had been completely obliterated, save for the few small bits that were now welded to the busbars when the screwdriver first made contact.
My first mistake was using an uninsulated screwdriver, and my second mistake was allowing myself to be distracted with my pinkies inside a live board. As fortune would have it I was wearing rubber soled boots and stood on a fibreglass ladder at the time, if I hadn't then I suspect the outcome would have been quite different because 3 phase doesn't give you a chance like domestic 230 does.
Anyway, I digress.......the reason I put the word qualified in block caps is because I was unsure of your ability/confidence in playing with electricity.....and a simple oversight could quite easily result in early demise.
Memory lane moment ;D ;D
Remember watching my dad working on a Hyster electric forklift one saturday morning when I was a kid.
He knocked a stilson off and it landed across the 2 main terminals :o
First there was a spark ............... then like a low buzzing sound .............. then the tinker started to glow :o :o
After one attempt at kicking it off, we ran away :y :y
I knew he was the service manager there and they was nobody else working that day but don't know how he got away with that ::) ::)
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I thought it may have been water getting into an outside light....doesnt seem so tho....ive disconnected them.....it still trips.
Went round and unplugged all the low energy bulbs.....it still trips.
Swapped the 5amp circuit breaker in the consumer unit with a spare i had......still trips
Out of ideas now.....so
Phoned a sparky....he's popping round to take a look....but if its not a quick fix.....he reckons he is free on Friday
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Not if your friendly electric board man gives you a bag of lead seals you don't :-X ;D
One of the things I noticed when I moved into my new place (1970 built, 1970 electrics, 1970 gas meter..) was that there were no seals on anything in the cupboard - not the fuse, not the gas meter, nothing. Still, at least it means nobody can tell.. ;D
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job jobbed :y
Sparky has just left, cost me £100, but at least the lights stay on now....
Bet you carnt guess what the problem was.....the sparky reckons its a fairly common fault....
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Bet you carnt guess what the problem was.....the sparky reckons its a fairly common fault....
Dog hair in a light switch?
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Bet you carnt guess what the problem was.....the sparky reckons its a fairly common fault....
Dog hair in a light switch?
Nope.....
He changed all lighting wiring in the loft above the kitchen that fed the downlighters......but the fault was still there.....
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Spider in a downlight?
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Spider in a downlight?
Nope.....i gave you a clue in my last post.......he didnt replace the cable for fun.......and it was pvc type cable.
Then he moved onto the bathroom, which is downstairs next to the kitchen and has a flat roof of it.
So no easy access to the wiring.
However his mega, showed no fault in the bathroom wiring. tested at the switch for the bathroom light.........
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Faulty light fitting caused by heat/sub-standard manufacturing?
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Rodent damage ??? Sure you had furry visitors recently :-\
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You are correct LD the little bastards had been chewing on all wires in the loft but the main fault where they had completely chewed through the cable was the feed to the bathroom hidden in the flat roof but luckly easy to replace
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What was the prize? ::) :D
Just had a vague recollection of you having visitors and thought about it :y
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What was the prize? ::) :D
Just had a vague recollection of you having visitors and thought about it :y
Well, he was either extremely lucky and chewed to neutral first so the breaker tripped or he's dead ;D
And the sparky agreed this could have been like this for weeks, hence the 'red herring' the earth trip was giving......ie starting tripping every few days, then daily, then every 15mins or sometimes straight away.
Last night for example the trip was going as soon as i tried to turn on the lighting circuit. This morning first thing the sparky did was turn on the circuit and it came on.....we were chatting in the kitchen about it being sod's law it behaves when you dont want it to.....15mins later the earth breaker tripped.
No prize i afraid LD......tho you can be smug for being a smart arse congratulate yourself for being correct :D ;D