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Who's a sparky?

Discussion in 'The Pub' at netrider.net.au started by vic, Sep 2, 2009.

  1. I have an electrical issue at home.



    I have a power point in the roof.

    It is a power point and a switch for a light. The heater plugs into the power point.

    There is also an "extension lead" that runs across the roof that powers the evap cooler. This lead is wired into the power point.

    For 5 years it all worked fine. Then this year at supers time the control room calls me to tell me there is a mains fail.
    Wife gets home and half the house is out. The RCD has tripped and will not reset.

    I get her to call a sparky and the bloke was a dick, he knocked out the power going to the roof as his way of fixing it.

    When I got home I had a look and couldnt see anything wrong with the wiring or the switches, nothing was burnt out nothing had chewed through the cables etc etc.

    I got around the problem by running a few leads to other circuits and everything worked fine.

    Now I don't like leads hanging around everywhere so on the weekend I decided to clean it all up and replace the switch.

    All good until I plugged the evap cooler in to the "extension lead" it tripped the RCD again.

    Today I pulled it all apart and ensured that there were no strands of wires touching a neighboring wire.

    Tested the "extension lead" with a different appliance and it didn't trip.

    WOOT!!!!!

    I proceed to snake the "extension lead" across the roof space and plug the cooler in and the RCD tripped again :mad:

    I'm at a loss as to why it's tripping the RCD. Obviously it is leaking to earth but why?

    To an uneducated person like me ;) it makes no sense.

    Neither the cooler or the heater were running at the time. It just trips the RCD whenever the cooler is plugged in.

    Those in the know have any idea why all of a sudden after 5 years the thing decides to trip the RCD?
     
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  2. I'm not a sparky Vic but several years ago I had a PCB in my household air con cook it's self and do exactly the same thing, also 5 years and two months old (five year warranty).
    Mine was apparently caused by a fan failure overloading some bit of the pcb.
    After the initial failure it didn't have to be switched on to drop the breaker.(hard wired to switch in metre box).
     
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  3. Cheers,

    The cooler works perfectly well though in this case.

    I experienced something similar years ago. A fridge was working perfectly well. Moved it across town and donated it to a friend. It was upright all the time. Got it in place, plugged it in and before I had a chance to turn the switch on the power point it was tripping the RCD :?

    They threw it away ;)
     
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  4. i am doing an electrical pre-app so i might be way off ;) excuse me if i am :)

    an rcd trips when there is a change in current. (at least i think thats the one ;) ) which means that something inside the cooler must be gone...

    haha, sorry... still learning. i can ask tomorrow at tafe though, if no one can help you :)

    anyone want an apprentice? ;)

    cheers :)
     
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  5. I'm a sparky,

    The RCD works by measuring current going through a thoroid coil (active) then measuring the return current through the coil (neutral).

    So for the RCD to trip everytime you plug the cooler in, the problem is in the cooler somewhere, either the wiring is damaged or the fan motor is faulty.

    Cheers Darryl
     
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  6. Cheers for that triumph1979

    But when I plug the cooler into another circuit it behaves and does not trip the RCD. I've had it plugged into a different circuit for over 6 months without an issue.

    I've tested the lead that it plugs into with the clothes dryer and it does not trip.

    As silly as it sounds, it only trips the RCD when the cooler is plugged into that one "extension lead"
     
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  7. Did you try a different extension lead between the cooler and the power point?
     
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  8. Ok Vic,

    A RCD will Trip when the total circuit insulation is low, so i would suggest unpluging one thin at a time( leave the cooler in) until the rcd doesn't trip.

    Start with any electrical equipment thats has a element or a fan as these normally the problem.

    Hope this help.

    Cheers Triumph1979
     
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