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Live - Neutral reverse from plug in tester

Former Community Member
Former Community Member

Hi, being retired for 2 years i was in trade as domestic electrcian for 10 years then commercail for next 40 years. So have high level od experience in field, yet never experienced the below unrational fault.

Really baffling me now (and an  independant competant electrican contractor) is a recent problem where i found using Martindale plug in tester (also using  independant contractors KEW plug in tester) that on a ring circuit somewhare in its middle 2 outlets read L-N reverse.

Yet taking off the outlets, the cables are connected correctly and live tested live in its correct position so Plug top fuse was correctly protecting appliances. This is on a recently extended ring circuit for room extension. I have read other blogs where they say the earth could be live or at least have a voltage presence, or that the earth CPC in fact could be floating so having volts induced to it.  Both scary thoughts.   

Any one had same issue please and what was found to then correct fault. 

I have yet to do a local earth test of the cpc at the two outlets and check the consumer unit earth connection to the main incoming supply.  Also all other outlets in house test correctly so assume main earth connection is not a problem and the RCD as main isolator passes its tests,

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  • 0

    AJJewsbury: 
     

    it does not help when electricians don't twist them together, if they did but not terminated at least the ring would e maintained to other outlets. 

    Twisting solid-core conductors is often considered poor practice these day - as it means damaging the conductors if they need to be separated for testing or fault-finding. On a ring a single fault won't loose Earth to other accessories since there'll still be continuity around the other side of the ring - but the fault would be easily detectable by a routine end-end test from the CU.

       - Andy.

    I always twist the C.P.C.s of 1.0mm2 and 1.5mm2 together. It makes a good joint. If sufficient spare wire is left and the wires are damaged if untwisted, it is easy to re-terminate the wires if needs be. Single small solid copper conductors terminated into terminals without doubling the end over or twisting more than one together can come loose or indeed not be held in the terminal securely.

     

    I always trim back any copper solid conductor that has been deformed by a screw, as if not, the wire can snap/break when moved about whilst refitting an accessory. This applies to untwisted single wires as well.

    Z.

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  • 0

    AJJewsbury: 
     

    it does not help when electricians don't twist them together, if they did but not terminated at least the ring would e maintained to other outlets. 

    Twisting solid-core conductors is often considered poor practice these day - as it means damaging the conductors if they need to be separated for testing or fault-finding. On a ring a single fault won't loose Earth to other accessories since there'll still be continuity around the other side of the ring - but the fault would be easily detectable by a routine end-end test from the CU.

       - Andy.

    I always twist the C.P.C.s of 1.0mm2 and 1.5mm2 together. It makes a good joint. If sufficient spare wire is left and the wires are damaged if untwisted, it is easy to re-terminate the wires if needs be. Single small solid copper conductors terminated into terminals without doubling the end over or twisting more than one together can come loose or indeed not be held in the terminal securely.

     

    I always trim back any copper solid conductor that has been deformed by a screw, as if not, the wire can snap/break when moved about whilst refitting an accessory. This applies to untwisted single wires as well.

    Z.

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