Ring Main keeps "tripping"

Discussion in 'Electrics UK' started by thefibreguy, 9 Oct 2010.

  1. thefibreguy

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    Good Afternoon Gents,

    I have a ring main, divided between my kitchen, & lounge ( I know this is not ideal, but was like this when we moved in 15 years ago!!!)

    The Kitchen has 4 doubles, & the lounge has 3 doubles, they are never all used together, we don't even have an electric kettle!!

    Last night, at 10pm, the Mini breaker feeding the ring main(32A), tripped.

    I tried resetting, but it wont even lock on now, just trips to the off position.

    I have unplugged every plug from the sockets on the ring, but is still tripping!!

    I have not started taking the sockets off the walls yet to check for the obvious, ie loose cable shorting something, any other way of quickly 'DIY' testing the ring to check for a silly little fault, ie faulty breaker?

    I have not recently worked on/extented the ring, its never been overloaded, so cant understand why it would just fail.

    Thanks in advance.
     
  2. plugwash

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    The first thing to do is to check if it's a faulty breaker, easiest way to do this is probablly to disconnect the wiring from the breaker (with the power off), tape it up so it can't short to anything, turn the power back on and try to reset the breaker. If the breaker won't stay on even with nothing connected then you need a new breaker.

    Assuming it's not the breaker I'd think the first thing to do is to inspect as much of the ring as you can.

    I would start by taking off every socket one by one and looking for any signs of damaged insulation, both on the wires and on the sockets themselves. Damaged wire insulation can generally be fixed with sleeving, damage to the socket backs should be dealt with by replacing the sockets.

    If the ring runs through a crawlspace go down there and inspect as much of the cable as you can

    Also try to map out the ring while you are at the inspection ready for the next stage.

    If inspection fails to find the problem then you need to break the ring down into individual accessories and runs of cable and test each accessory and each run of cable for shorts (ideally an insulation resistance tester but a multimeter on it's highest resistance range will probably find the fault)
     
  3. OwainDIYer

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    Have you put any pictures up recently?
     
  4. ColJack

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    or tightened / replaced any screws such as in a door hinge?
    or stripped the paper off a wall in a room nearby or above?
    or re-fixed a squeaky floorboard anywhere upstairs?

    do you have an outside socket?
    heard any scurrying in the ceiling above the 2 rooms recently?
     
  5. sparkwright

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    Any outdoor lighting or outhouses connected to this circuit?
     
  6. sparkydude

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    You say you have unplugged everything from the circuit, but have you turned everything off ?? Do you have any built in appliances on the circuit in question IE fan oven ????
    Make sure EVERYTHING is unpliugged or turned off and try again.

    Could ba a faulty MCB but doubtful, More likeley a wiring fault.

    Nick
     
  7. thefibreguy

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    Guys,

    Thanks for all your replies, I have had a busy afternoon. I disconnected both sides of the ring at the breaker, & tested each section for shorting. I got lucky, It was the first leg, which just happens to run into the kitchen!!. I have left this leg disconnected, & am now feeding the lounge on a single leg. Its only running the TV/Sky, phone, & internet. I will get an electrician to investigate/replace the damaged leg.

    Regards
     
  8. sparkydude

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    Just one thing is worrying me, Have you broken the ring main up somewhere then ? as if you have isolated the faulty leg of the ring at the board then without breaking the ring apart at another point you have effectiveley go two radials from one MCB if by simply removing one leg from the DB , the problem dissapears then you have got a dead short somehwere that is not on a part of the ring but on a dead leg .

    Nick
     
  9. securespark

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    Yeah, TFG, it does sound like you either have a broken ring already or two radials running off this 32A breaker.

    Either way, it needs a pro to look at it.
     
  10. thefibreguy

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    I have it disconnected in two locations, at the breaker, & at the rear of a double socket in the lounge, breaking the ring in the middle, so I think I have created one working radial. the other leg of 3 doubles in the kitchen is dead.

    To get a new cable in is gonna be a major job. My kitchen floors are now concrete/tiled, & have units on all walls. To be honest I am gonna do it proper, make one ring for the kitchen, & one for the lounge, like it should be.

    Guess I better start saving, the rates you boys charge!!!!

    Thanks again.
     
  11. ColJack

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    you can isolate it even further..

    reconnect it in the lounge socket, then split it at each kitchen socket in turn.
    at least that way you know which 2 sockets or it's between, or the first and the board..

    you didn't answer the questions above, have you put in any nails, screws or done some other form of DIY in, adjacent to, above or below the rooms in question?
     
  12. thefibreguy

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    No, no DIY whatsoever, so only thing I can think of is wear, & tare of cables, or rodent damage (we have 4 cats).

    Do electricians have a mains cable version of a telecoms cable TDR, which can locate the distance from the end that the cable is damaged?
     

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