Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Faulty Neutral and affects?

Options
  • 12-10-2018 10:41pm
    #1
    matjay
    Registered Users Posts: 68 ✭✭


    OK,

    So a while back I was having problems with intermittent tripping of the RCD. Had finally traced the problem back to the Dishwasher! But upon doing this I found that the socket it is plugged into has a faulty Neutral and there is power (approx 16 volts according to the Meter) running to it all the time even with the fuse switch turned off!

    A friend of my Dads (ex Irish Lights electrician) had a look and defo said its a faulty neutral and the cable needs replaced.

    This is being sorted as the guy that installed my kitchen moved this socket and must have damaged the neutral while moving it??

    Question is can a continuous power leakage to an appliance damage it. Since not using the Dishwasher on this socket and using an extension flex to a socket over counter, it has not tripped once? Until this evening!! Im thinking the continous feed of electricity may have damaged thr Dishwasher? Its a relatively new appliance (just under two years) Never had this problem with it before the socket was moved?

    Cheers


Comments

  • Options
    #2
    Andrea B.
    Registered Users Posts: 1,921 ✭✭✭Andrea B.


    matjay wrote: »
    OK,

    So a while back I was having problems with intermittent tripping of the RCD. Had finally traced the problem back to the Dishwasher! But upon doing this I found that the socket it is plugged into has a faulty Neutral and there is power (approx 16 volts according to the Meter) running to it all the time even with the fuse switch turned off!

    A friend of my Dads (ex Irish Lights electrician) had a look and defo said its a faulty neutral and the cable needs replaced.

    This is being sorted as the guy that installed my kitchen moved this socket and must have damaged the neutral while moving it??

    Question is can a continuous power leakage to an appliance damage it. Since not using the Dishwasher on this socket and using an extension flex to a socket over counter, it has not tripped once? Until this evening!! Im thinking the continous feed of electricity may have damaged thr Dishwasher? Its a relatively new appliance (just under two years) Never had this problem with it before the socket was moved?

    Cheers

    Without going too deep. If you have neutral voltage (measured to earth I presume) with RCD turned off, I doubt the cable alone is source of problem.
    The appliance damaged , anyone's guess, but imho, unlikely.


  • Options
    #3
    punisher5112
    Registered Users Posts: 24,647 ✭✭✭✭punisher5112


    In my in-laws house it was a dishwasher and the waste water pipe had a few cuts so the water was spraying out behind and in to the socket.

    They were getting shocks off the sink and rcd was occasionally tripping.

    Recently they turned the main power off for shower on it's isolating switch and turned back on.

    Luckily it didn't work as the neutral had been burning and the inside of the switch was badly melted.

    Cut off burnt cable and reconnected and tightened everything.


  • Options
    #4
    Sleeper12
    Registered Users Posts: 16,967 ✭✭✭✭Sleeper12


    punisher5112 wrote:
    They were getting shocks off the sink and rcd was occasionally tripping.


    I might want to check if the sink & pipes are earthed. I don't think they should have been getting shocks if it was earthed


  • Options
    #5
    matjay
    Registered Users Posts: 68 ✭✭matjay


    Andrea B. wrote: »
    Without going too deep. If you have neutral voltage (measured to earth I presume) with RCD turned off, I doubt the cable alone is source of problem.
    The appliance damaged , anyone's guess, but imho, unlikely.

    Thanks for the reply,

    Dishwasher went in new from a new Kitchen install. Was thinking that seeing there was a feed of electricity supplied to the neutral all the time (all be it low voltage). This may have shorted something inside the Dishwasher? Strange how this all started after the kitchen install?

    Cant see how this cant be bad for an appliance that is wired up to work the correctly?


  • Options
    #6
    AMKC
    Registered Users Posts: 15,734 ✭✭✭✭AMKC
    Ms


    matjay wrote: »
    OK,

    So a while back I was having problems with intermittent tripping of the RCD. Had finally traced the problem back to the Dishwasher! But upon doing this I found that the socket it is plugged into has a faulty Neutral and there is power (approx 16 volts according to the Meter) running to it all the time even with the fuse switch turned off!

    A friend of my Dads (ex Irish Lights electrician) had a look and defo said its a faulty neutral and the cable needs replaced.

    This is being sorted as the guy that installed my kitchen moved this socket and must have damaged the neutral while moving it??

    Question is can a continuous power leakage to an appliance damage it. Since not using the Dishwasher on this socket and using an extension flex to a socket over counter, it has not tripped once? Until this evening!! Im thinking the continous feed of electricity may have damaged thr Dishwasher? Its a relatively new appliance (just under two years) Never had this problem with it before the socket was moved?

    Cheers


    When you say your fuse switch is switched off I take it you man the mcb for the kitchen circuit is off. I am right?
    What you are reading in the neutral could be just capacitance from other cables. Had this recently myself while doing a job and two cables were reading as live because they were close to each other even do only one was connected to the live power and the other was just beside it but not connected or it could be because you have a faulty RCD.
    Have you turned off your RCD and then checked the neutral to see if there is still a reading on it? With the RCD off there should not be any reading or power in any sockets. If there is then the RCD is faulty and there must be a leakage through the neutral.


  • Advertisement
  • Options
    #7
    matjay
    Registered Users Posts: 68 ✭✭matjay


    AMKC wrote: »
    When you say your fuse switch is switched off I take it you man the mcb for the kitchen circuit is off. I am right?
    What you are reading in the neutral could be just capacitance from other cables. Had this recently myself while doing a job and two cables were reading as live because they were close to each other even do only one was connected to the live power and the other was just beside it but not connected or it could be because you have a faulty RCD.
    Have you turned off your RCD and then checked the neutral to see if there is still a reading on it? With the RCD off there should not be any reading or power in any sockets. If there is then the RCD is faulty and there must be a leakage through the neutral.

    Yeah friend of my Dads did all that and both cables dead when RCD turned off. He disconnected the cables that lead to the socket behind the Dishwasher under the counter and connected a lead with socket to see if it was the fuse switch that was causing the error but when he turned it off at the switch, no volts coming off the neutral dead as a dodo. So its defo a faulty neutral going down to the socket from the switch.

    Im just thinking that if it wasn't for the Dishwasher tripping and we had not found this fault. Would it have been a serious treat of electrical fire?

    Just hopenit hasn't knackered the Dishwasher as its only relatively news !!


  • Options
    #8
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    16v or more on open circuit wiring is not unusual when using digital multimeters.

    Capacitive coupling combined with very high impedance multimeters often show voltage on floating wiring that is in proximity to live circuits.


  • Options
    #9
    Tuco88
    Registered Users Posts: 1,052 ✭✭✭Tuco88


    If you have a fluke meter most have a "lo z" impedance feature you can turn on to remove the unwanted voltage.

    You will see this alot if you are working on motors.


  • Options
    #10
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,555 Mod ✭✭✭✭2011


    Bruthal wrote: »
    16v or more on open circuit wiring is not unusual when using digital multimeters.

    Capacitive coupling combined with very high impedance multimeters often show voltage on floating wiring that is in proximity to live circuits.

    Exactly.


    So what issues could there be with the neutral?
    External to the installation, poor insulation or conductor resistance is too high.

    So work through the possibilities:
    1) First confirm that the neutral is healthy at the main distribution board.

    2) Next determine if there is an issue with the insulation with the insulation by carrying out an insulation resistance test (frequently referred to as a "meggar test"). Measure the insulation between neutral and phase as well as neutral and earth. Only 1 MΩ is required, but many would not be happy with less than 50 MΩ in a domestic installation.

    3) Finally measure the resistance of the neutral conductor from the distribution board to the furthest point in the circuit. Compare this to an estimate of what it should be based on the length of run and resistance per meter.


Advertisement