Page 5 of 5 FirstFirst ... 345
Results 41 to 46 of 46

Thread: How to isolate an earth leakage problem

  1. #41
    Diamond Member Justloadit's Avatar
    Join Date
    Nov 2010
    Location
    Johannesburg
    Posts
    3,480
    Thanks
    134
    Thanked 695 Times in 593 Posts
    Blog Entries
    1
    Quote Originally Posted by AndyD View Post
    TBH I'm not sure why it would cause an RCD to trip, there's no current imbalance on the load side which is the criteria for tripping. I'd guess it's an anomaly with the internal electronics maybe.
    I think it has to do with reflected current flows in the E/N wires. All circuits connected to the council point on the E/N circuits are connected in parallel to all the different loads, however when there is a break on the council side supply line, as is the case described by ACEsterhuizen, and because of high current flows and inductance in these circuits, a pulse is injected into the neutral line towards the load side. THE RCD , by nature of its design, is to trip when there is an imbalance in the currents in the L and N circuits. When this pulse comes down the line, there is a mismatch between the L and N, and the RCD can not differentiate where the imbalance is coming from, source or load, and the mechanism then trips.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar pumping, Solar Geyser & Solar Security lighting solutions - www.microsolve.co.za

  2. Thanks given for this post:

    ACEsterhuizen (25-Jan-16)

  3. #42
    Bronze Member
    Join Date
    Mar 2012
    Location
    Account_Deleted
    Posts
    165
    Thanks
    122
    Thanked 23 Times in 18 Posts
    Hi Andy yes all is ok now thanks. and thank Justloadit I almost understand that.

  4. #43
    Diamond Member Justloadit's Avatar
    Join Date
    Nov 2010
    Location
    Johannesburg
    Posts
    3,480
    Thanks
    134
    Thanked 695 Times in 593 Posts
    Blog Entries
    1
    The pulse I am referring to is called EMF.
    Its the shock you get when you touch the coil contacts of a 12V relay, and disconnect the power to the coil, you feel a jolt. What happens is the inductance of the coil, because of the turns, causes a reverse voltage of several magnitudes greater then the supply in the opposite direction of the supply for a short duration of time. This is better seen when a relay contact breaks the current connection in a loaded circuit, and you see the spark across the contact points. This pulse is generated by the decaying magnetic field due to the loss of power, and depending on the current can be several hundreds of volts, in the case of a high voltage electrical system. The pulse in your application is propagated down the line through the ELB and discharges in the load Neutral to the earth of the equipment. The reason there is a flow of electricity is due to a capacitance between any 2 metals, the dielectric could be air, PVC or some other insulator.

    This capacitance effect is noted when running long wires side by side, and one wire is connected to N and the other is through a switch to L. When you place the multi-meter across the open switch wire, you get a reading of 100+ volts. This voltage is flowing between your meter high impedance input, and the capacitance caused by the wire PVC. This is also known as floating voltage.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar pumping, Solar Geyser & Solar Security lighting solutions - www.microsolve.co.za

  5. Thanks given for this post:

    ACEsterhuizen (02-Feb-16)

  6. #44
    New Member
    Join Date
    Jun 2017
    Location
    Cape Town
    Posts
    1
    Thanks
    0
    Thanked 0 Times in 0 Posts
    I've tried all this but ALL my plug circuits aren't working even though ALL breakers are up. Please help??

  7. #45
    Diamond Member AndyD's Avatar
    Join Date
    Jan 2010
    Location
    Cape Town
    Posts
    4,923
    Thanks
    576
    Thanked 934 Times in 755 Posts
    If all your circuit breakers are in the up position and there's no power at your sockets then it's not an earth leakage tripping problem. Possible a poor connection somewhere or even a faulty breaker but either way you'll need to get a sparky in woh has the test equipment to find the problem.
    _______________________________________________

    _______________________________________________

  8. #46
    Gold Member Sparks's Avatar
    Join Date
    Dec 2009
    Location
    Port Elizabeth
    Posts
    890
    Thanks
    20
    Thanked 127 Times in 96 Posts
    Quote Originally Posted by LloydJ View Post
    I've tried all this but ALL my plug circuits aren't working even though ALL breakers are up. Please help??
    It sounds simple, but are you sure the breakers are up? I have often asked a client this and when I get to site I see it has tripped. Especially when the board is high it might appear as though it has not tripped because the lever does not come all the way down. Physically feel whether the breaker is up or half-way down(tripped). If all the plug circuits are dead there is no supply coming through the ELCB or to it.

Page 5 of 5 FirstFirst ... 345

Similar Threads

  1. Geyser not on earth leakage
    By Goobie in forum Electrical Contracting Industry Forum
    Replies: 21
    Last Post: 03-Jan-19, 05:44 PM
  2. Does a stove need to be on an earth leakage?
    By Leecatt in forum Electrical Contracting Industry Forum
    Replies: 63
    Last Post: 23-Jan-18, 08:26 AM
  3. Earth Leakage
    By Pieter00 in forum Electrical Contracting Industry Forum
    Replies: 13
    Last Post: 27-May-13, 12:03 PM
  4. Random earth leakage problem
    By BillH in forum Electrical Contracting Industry Forum
    Replies: 39
    Last Post: 23-Jan-12, 09:37 PM
  5. CBI earth leakage units
    By murdock in forum Electrical Contracting Industry Forum
    Replies: 2
    Last Post: 29-Oct-09, 12:44 PM

Did you like this article? Share it with your favourite social network.

Did you like this article? Share it with your favourite social network.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •