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Thread: Plug circuit works but no neutral return path

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    Plug circuit works but no neutral return path

    I'm not an electrician, but have a fair DIY understanding of single phase electrical wiring.

    A lot of building and electrical work was done on my partner's house immediately before she moved in. All the lights/plugs etc work, but she's had intermittent tripping that I tried to fix this weekend. I found a rats nest of wires in the DB, as well as loose wires that I assume went to plugs/lights etc that were removed in the rebuild.

    I was hoping to fix the obvious faults and then bring in a qualified pro to check / fix and sign off on the CoC.

    Here's my (very confusing) problem. The house has a plug circuit that has been wired to bypass Earth leakage. It trips the ELCB as soon as I try connect it correctly. I followed the instructions AndyD posted to track down EL problems with no luck, but here is the thing: as long as the circuit bypasses the ELCB the circuit works EVEN IF all the neutrals are disconnected. I even disconnected the mains neutral in the DB and the circuit STILL works.

    Is there something obvious I can look for, or is this clearly a job for a qualified electrician?

    Many thanks for any ideas.

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    Site Caretaker Dave A's Avatar
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    It seems likely the returning neutral is connected to earth.

    Quote Originally Posted by DavyR View Post
    A lot of building and electrical work was done on my partner's house immediately before she moved in.
    The contractor that did the electrical work should issue the CoC on the work they have done.
    (It was done by a registered electrical contractor, right?)
    The trouble with opportunity is it normally comes dressed up as work.

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    Thanks for the insight Dave. I had no idea that a circuit would work if the neutral is connected to earth.

    Re the contractor who did the work... don't ask. It was a nightmare and my partner eventually just gave up. There is no way the electrics were compliant but she wasn't willing to take the matter further. With my little knowledge I've solved the tripping problems (bar this one), replaced non working plug points, fixed the shocking shower, replaced the household light switch that was used as an isolator for the second geyser, routed new cabling to the other geyser, added bonding, removed unused breakers, stopped the geyser leak that was dripping onto the bathroom light circuit .... you get the point.

    I'm hoping your guidance will help me find and fix this last problem and then I can bring in a qualified electrician to check my work and fix what's still broken or what I've messed up

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    Site Caretaker Dave A's Avatar
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    Quote Originally Posted by DavyR View Post
    Thanks for the insight Dave. I had no idea that a circuit would work if the neutral is connected to earth.
    If you've disconnected all the neutrals including the main supply neutral, there's really only one return route option left...

    A word of caution - when it comes to electrical installations, the gap between "functionally working" and "compliant" is HUGE.
    Personally I'd suggest you start with getting a test from an installation electrician before fiddling any further. Some significant potential problems are not visibly obvious and require the correct instruments and tests to discover. A neutral to earth fault could be the tip of the iceberg.
    The trouble with opportunity is it normally comes dressed up as work.

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    Diamond Member AndyD's Avatar
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    Quote Originally Posted by DavyR View Post
    ....Here's my (very confusing) problem. The house has a plug circuit that has been wired to bypass Earth leakage. It trips the ELCB as soon as I try connect it correctly. I followed the instructions AndyD posted to track down EL problems with no luck......
    The advice I posted about earth leakage problems wouldn't cover problems caused by incorrect or fundamentally flawed wiring I'm afraid. It was aimed at assisting the tracking down of problems on circuits that were originally installed correctly and subsequently went faulty.


    Quote Originally Posted by DavyR View Post
    but here is the thing: as long as the circuit bypasses the ELCB the circuit works EVEN IF all the neutrals are disconnected. I even disconnected the mains neutral in the DB and the circuit STILL works.

    Is there something obvious I can look for, or is this clearly a job for a qualified electrician?
    From what you say there's a good likelyhood you have a fault on the circuit that could result in someone getting a shock. My best advice would be to leave the circuit disconnected and get assistance from an experianced sparky with appropriate test equipment.


    Quote Originally Posted by DavyR View Post
    With my little knowledge I've solved the tripping problems (bar this one), replaced non working plug points, fixed the shocking shower...
    If there was a shower (or any other appliance for that matter) giving shocks then there's actually two faults that need finding and fixing. Firstly there's a leakage fault that is providing at least a partial path between the current carrying conductors and the item in question and secondly there's inadequate earthing that is allowing a 'touch voltage' to develope. Especially with a shower which is in a zone that's considered high risk of injury or fatality in the case of a shock, please get an experienced electrician to inspect and test the circuit.

    Quote Originally Posted by DavyR View Post
    replaced the household light switch that was used as an isolator for the second geyser,
    The physical size of a switch isn't an indication of it's suitability as a geyser isolator. You do get standard grid switches that are rated 20A and are double pole, same size as standard light switches.

    I'm with Dave, I'd also suggest you now get a qualified sparky to inspect and test the installation. Once you have the results you can discuss with him the best way forward to firstly making the installation safe and then compliant. There may be areas of the remedial work he'd be happy for you to do (under his guidance) in order to keep the labour time and costs down.
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    The fact that you disconnected the "Mains" neutral in the DB is a dead give-away that as Dave said, there is an earth fault or from what I have read here the electrician is using the earth wire because the neutral is damaged. Before you use the installation further, isolate that circuit by removing the "live" supply to it by physically removing the red wire from the circuit breaker then get a competent electrician to see if there is just a bad termination or if that circuit needs re-wiring.

    To find out who/what is a "Competent" electrician look at the "sticky" at the top of this forum: http://www.theforumsa.co.za/forums/s...ance-explained

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