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current flow in earthing point problem????

Discussion in 'Troubleshooting and Repair' started by joseph1911, Nov 22, 2015.

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  1. joseph1911

    joseph1911

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    Nov 22, 2015
    My switch board is not showing current flow in earth socket but when I connect any power cable in it, the cable shows current flow in earth. Cable is OK because I tested it in other sockets. Got me all confused, any suggestions??
     
  2. Minder

    Minder

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    Apr 24, 2015
    Way more information needed!!
    M.
     
  3. Martaine2005

    Martaine2005

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    May 12, 2015
    That's a good thing in the UK!.

    Martin
     
  4. Minder

    Minder

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    Apr 24, 2015
    A good thing just about everywhere!

    I suspect that there is an earth on the item being plugged in to the outlet, or possibly the outlet is miswired as the other outlets are OK?
    Or possibly they do not have an earth conductor.!
    M.
     
    Martaine2005 likes this.
  5. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    Current in the earth wire happens all the time, it's the amount of current that's important.
    Adam
     
    Martaine2005 likes this.
  6. Minder

    Minder

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    Not in my house it doesn't I would be getting a lot of GFI trips if it were.
    Or do you mean Often?
    M.
     
    davenn likes this.
  7. davenn

    davenn Moderator

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    agree with minder
    that doesn't sound right, Adam
     
  8. Bluejets

    Bluejets

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    Adam is correct.
    Unless everyone else has equipment with infinity insulation resistance.
    This is why most domestic core balance relays ( safety switches) have a trip level of 30mA.
    I suspect the op is operating in unknown territory as can be seen by the rather limited information on the outcome of the test performed or any circuit to explan the connections.
    Above assuming MEN earthing system.
     
  9. davenn

    davenn Moderator

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    There's only current flowing in the earth lead of an appliance IF there is an earth fault in the device
    otherwise there is no circuit for current to flow
     
  10. Bluejets

    Bluejets

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    Oct 5, 2014
    Not an earth fault as such, rather an insulation resistance less than infinity.
    Take any magnesium dioxide insulation heat element ( stove or hot water element) ....an acceptable level of insulation resistance here is 0.5 meg ohm.
    Other examples in appliances is a minimum of 1 meg ohm.
    I'll leave the calculations to others but facts are correct.
     
    duke37 likes this.
  11. Minder

    Minder

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    I suspect that is stretching it AFA what the OP seems to be experiencing, depending on the sophistication of the equipment he is using to measure the earth current?
    M.
     
    davenn likes this.
  12. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    In Australia, earth and neutral are bonded together and current is shared between the earth and neutral connections.

    The earth stake is often connected to copper water pipes, and where the connection to the meter is copper, this effectively joins the earth of all the houses in a street.

    If a water meter is replaced, a link is placed across the meter before it is removed and left on until the new meter is fitted. If the house has a neutral fault and poor earthing, all current is flowing via the earth, and removing the meter can cause the house side of the pipe to lift to mains potential.

    Even with a good earth and no neutral fault, current is shared between the earth and neutral circuits.

    note that the bonding between earth and neutral occurs after any rcd style breakers, and any current at this point is not a fault current.
     
  13. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    "In Australia, earth and neutral are bonded together and current is shared between the earth and neutral connections."

    Where do you get this from ????

    I'm glad you don't do any house wiring.
     
  14. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Australian standards.

    Google "Multiple Earth Neutral"

    Here's a simple diagram with references to the relevant clauses. And here is a FAQ from Standards Australia (good enough for you?). Read from page 4 to about page 7. It specifically mentions the bonding wire between earth and neutral.

    Why? Might I accidentally do it correctly?
     
  15. joseph1911

    joseph1911

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    Nov 22, 2015
    I am from India, can this be a problem in house wiring?
     
  16. joseph1911

    joseph1911

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    Nov 22, 2015
    Thanks for your answer I don't think there is a earth conductor here ,that may be the case you say?
     
  17. Arouse1973

    Arouse1973 Adam

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    Yep. But not just the insulation resistance. Every mains filter that has a connection from live to earth (Y type capacitor) will inject a current into earth. This is why there is a maximum value of capacitance, so to be below the 30 mA trip value. But some equipment like a LISN (line input stabilization network) used for EMC testing can't be connected to an RCD because they would trip out all the time.

    Adam
     
  18. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Possibly. Have you measured the neutral current? (I assume you're using a champ type meter).

    My reading trends to suggest that India may use an MEN system, but I'm very aware of the level of standards compliance in India. If you see that there is both neutral and earth current and that they sum to the current on the active, then it might be perfectly ok.

    The best thing to do would be to find a reliable electrician and get their opinion.
     
    Arouse1973 likes this.
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