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Thread: ELU turns off after power goes back on

  1. #1
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    ELU turns off after power goes back on

    I can recall some one posting something of this nature some time back, but after load shedding
    this particular earth leakage unit trips. It can be reset straight away and all is well.

    Has anyone experienced this type of thing and what could be causing it.

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    There could be surge arrestor plug tops on the circuit - On switch on there are slight surges been taken to earth which causes the imbalance and the unit trips.
    Switch mode power supplies, like found in PC''s , also have a habit of doing that.

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    Quote Originally Posted by ELECT 1 View Post
    I can recall some one posting something of this nature some time back, but after load shedding
    this particular earth leakage unit trips. It can be reset straight away and all is well.

    Has anyone experienced this type of thing and what could be causing it.
    Was called out yesterday for the same thing.

    It was one of those old 20 mA sensitivity units.

    We created our own blackouts by turning the main breaker off and then on again and each time, the unit would trip.

    Replaced with a new CBI 30 mA ELR and problem solved.


    Cheers & peace out ... Derek

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    Yip, i also just replaced it.

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    I also found that surge arrester plugtops(0.1 mega ohms),transformers in gate motors (0.5 mega ohms) and the transformer for the alarm(0.5 mega ohms) would just wait for something to trigger them.

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    The question is did you fix the problem or just prolong it... get a current clamp meter which can test mA ...you will be able to determine if it was at the threshold which caused it to trip already or if it was just a faulty e/l unit.

    Just remember to put the insulation resistance on 250 V so that you dont pop the MOVs in the plug tops.
    Comments are based on opinion...not always facts....that's why people use an alias.

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    I found that with the transformers and surge arrester plugtop the earth leakage sensitivity was less than 10ma and with them isolated the sensitivity was between 25ma and 30ma. So I wrote it in my report and suggested the replacement of transformers and taking of plugtop to prevent nuisance tripping.

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