Posting a message to the forum will remove the above advertisement
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. angel While you're here, would you mind checking out our Electrician's Insurance section to see if we could save you a few quid? - Specifically our Van Insurance Deals and Public Liability Insurance Deals. Thanks for supporting the forum! angel

    5% Discount from Electrical2Go.co.uk for ALL members! - Click Here

Discuss ELCB and Lightning in the Electrical Forum area at ElectrciansForums.co.uk.

Thread Status:
Not open for further replies.
Please make sure you checkout our forum sponsors, many do discounts for members and, they keep the forum free to use.
  1. Vmaxx Kingdom
    Offline

    Vmaxx Kingdom Guest

    Hi guys,
    i am from indonesia, i install CCTV system at Highway and the panel equipped with RCD
    i need to understand few question

    my RCD trip frequently ( in 1 month average 2-3 times)more whose if raining with thunder storm.
    info = RCD 40Amp, 0.1mA, earth resistance 0.5 Ohm.
    Q1 - Why this always happen
    Q 2 - which more sensitive , 0.1mA, 0.01mA, 0.03mA
    Q3 - what i have to do to prevent this
     
    Last edited by a moderator: Feb 17, 2012
  2. Marvo
    Offline

    Marvo Admin and gender confused Staff Member

    Location:
    South Africa
    When you say 'earth resistance' what do you mean. How did you measure this? Also what tester were you using when you got this reading?



    I think you answered this question when you said it trips when it rains. There's obviously rain water getting into the wiring or components causing a low insulation fault (IR fault).


    Are you sure the figures you listed are right. RCD's usually come in 10mA (0.01A), 30mA (0.03A), 100mA (0.1A) etc. The 100mA is the least sensitive of the three values I gave.

    Find the leak where the rainwater is getting in, fix it and repair any damage.
     
    Last edited: Feb 17, 2012
  3. Vmaxx Kingdom
    Offline

    Vmaxx Kingdom Guest

    1st, i said tq very much for the reply,

    earth resistance tested using earth tester.
    http://www.kew-ltd.co.jp/en/download/pdf/4102A_4105A_E.pdf


    for your info, i do the insulation test for whole circuit and the insulation still good. that mean no short circuit between live and earth, neutral and earth and live to neutral.
    if u though :-
    1) lightning may course the tripping - this system have lightning arrester . its should be discharge power surge directly to ground is i am right?
    2) and no water getting the to equipment, my outdoor panel water resistance

    tq again for the reply. hope i get learn something new again.
     
  4. Engineer54
    Offline

    Engineer54 Guest

    You said you IR tested the complete system. So what sort of IR value did you see for the overall (complete) system??
     
  5. Marvo
    Offline

    Marvo Admin and gender confused Staff Member

    Location:
    South Africa
    Yes, close proximity lightning could cause RCD tripping. This would be a likely cause if your system is testing good insulation. Surge arrestors will dump to earth when the surge is higher than the clamping voltage.

    Can you wire the surge arrestors on to the supply side of the RCD? If not maybe consider an RCD with automatic restart.

    I hate Flash websites but this was the best link I could find.
     
    • Like Like x 1
  6. Vmaxx Kingdom
    Offline

    Vmaxx Kingdom Guest

    live to neutral=230 Ohm
    live to earth = 150 Ohm
    Neutral to earth = 110 Ohm
     
  7. Vmaxx Kingdom
    Offline

    Vmaxx Kingdom Guest

    we try to reduce the project cost, this is maintenance after installation project (under warranty)

    is there possibility tripping issue course by the earthing rod sharing between lighting arrester and earthing terminal from the panel?
     
  8. Engineer54
    Offline

    Engineer54 Guest

    Are you sure your doing IR tests or resistance tests?? We should be seeing IR results in Meg ohms not ohms.... What test voltage are you using for your IR tests. Hope your not using the low ohm section on your IR tester, or using a multimeter for these tests?? lol!!
     
    • Like Like x 1
  9. Marvo
    Offline

    Marvo Admin and gender confused Staff Member

    Location:
    South Africa
    You say the insulation tests showed good insulation then you say that 'live to earth = 150 Ohm, Neutral to earth = 110 Ohm'.

    These reading do not show that 'the insulation is good'. These readings show low insulation, you need to improve the IR to at least 1 M Ohm live to earth and 1 M Ohm neutral to earth.

    Don't waste time replacing or rewiring the RCD, it's doing its job correctly with the readings you've given.
     
  10. Vmaxx Kingdom
    Offline

    Vmaxx Kingdom Guest

    lol... yes Meg Ohm. sorry,
     
  11. Engineer54
    Offline

    Engineer54 Guest

    Just realised your working on CCTV equipment. So i doubt if you have been conducting IR tests on that stuff except maybe between L N+E otherwise your electronics will be fried, ...well damaged anyway...lol!!
     
    • Like Like x 1
  12. Marvo
    Offline

    Marvo Admin and gender confused Staff Member

    Location:
    South Africa
    I assumed he would be doing IR tests at 250volts which should be adequate.
     
    • Like Like x 1
  13. Vmaxx Kingdom
    Offline

    Vmaxx Kingdom Guest

    i unplug dc equipment and should be not risk my equipment right?
     
  14. Engineer54
    Offline

    Engineer54 Guest

    Correct, ...You would need to unplug/disconnect all electronic mains power connections to be able to conduct IR tests on supplying/distribution cables, if you want to test between L-N, L-E, N-E at 250V or 500V...!! lol!!
     
Thread Status:
Not open for further replies.

Share This Page

Electricians Directory Post a Domestic Job Post a Commercial Job