ELECTRIC FULLY TRIPPING OUT - please help!

Discussion in 'Electrics UK' started by cashka76, 26 Oct 2006.

This topic originated from the How to page called Identifying a faulty circuit.

  1. cashka76

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    Hope you can help. Our Hager consumer unit is tripping out intermittently (maybe about once a day). It is the MAIN switch that goes, not just one of the individual fuses, so we are really stumped as to where the problem could be. I have noticed over the last week that it tends to happen at about 6.30 in the morning!!! Is it possible that there is some kind of incoming surge in power at that time that results in the whole thing blowing?

    Hope you can help shed some light!

    Claire
     
  2. Inky Pete

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    The problem's going to be something internal to the house, not any kind of incoming surge.

    What time does your heating come on in the morning?
     
  3. slippyr4

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    is your "main switch" actually an RCD? with a test button, and something like 60A/30mA written on it?

    A isolator switch will not turn itself off unless you have poltergeists.
     
  4. industryspark

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    im thinking the post is reffering to an RCD.

    if it happens consistently at the same time then the fault should be easy to find.

    once you think you know the offending circuit, you could leave that circuit off for a few days running to see if that is indeed the problem.
     
  5. Steve

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    Definitely an RCD. What sort of earth system do you have? Unless its TT, with an earth rod, theres no need for the mainswitch to be an RCD (and it shouldn't be, for the reason you've highlighted in your post - all the electric goes off it theres a fault). An electrician could alter this setup for you. I reckon your heating is set to come on at 6:30 ;)
     
  6. Markir

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  7. chrisbyrd

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    does anything else come on at 6.30? anyone getting up early for a shower?
     
  8. Big_Spark

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    Claire, check the timer settings for your heating system or water heating system (Immersion), whichever you have. It could be that one of the parts of this system has developed a fault and is causing the trip.

    Also, what time do you and your partner rise in the morning? Is there something about your routine that could shed some light on the matter? Do you have an electric or power shower that is invariably used at about 06:30?

    Have a good think, it is likely to be something simple to identify when you check everything.
     
  9. Invisible-Man

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    Am I right in thinking that if you were to detect the circuit of the fault (so happens to be a neutral/earth fault), then isolate via keeping mcb switched off on that circuit the fault would still trip a RCD !!!
     
  10. securespark

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    If it's an N/E fault, yes. If an L/E fault, it is possible to isolate it by switching mcb off.
     
  11. ricicle

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    Neutral/earth fault can trip RCD with its Phase conductor isolated - it depends if there are any other circuits drawing current giving rise to imbalance in the RCD because of their neutral current leaking to earth via the fault
     
  12. Invisible-Man

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    The point I was getting to, is that to completely isolate a found fault (neutral/earth) not knowing the reason for it and not a plugged in item, you would have to say in a immersion heater physically un-wire the heater to stop the RCD from tripping rather than switching the MCB off, maybe a difficult task for a DIY'er, and could make tracking down a fault a bit more difficult than just isolating a circuit by switching MCB's off one by one, thus throwing a DIY'er off the scent as it were
     
  13. JohnD

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    An immersion heater is very likely to have a local DP switch for isolation. So are other fixed appliances like cookers. Non-fixed appliances will have a plug you can pull out.
     
  14. Big_Spark

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    Invisible, John is right, and as far as I am aware, to comply with Britich Standards, FCU's need to be Double Pole switched anyway, so it is likely that you would isolate the fault by turning off the offending equipment..

    Could be wrong on the DP requirement for the FCU's though..anyone know the exact position on this?
     
  15. securespark

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    As far as I remember, there is no requirement to switch the neutral, but a DP switch is considered good practice.
     

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