Another newbie insulation testing question...

Discussion in 'Electricians' Talk' started by Beacon, Mar 27, 2019.

  1. peter palmer

    peter palmer Well-Known Member

    Because if the neutral is connected to the bar when you test then you are testing every other circuit at the same time.
     
  2. Beacon

    Beacon New Member

    But the line conductor of the circuit is removed from the mcb for test - so cannot be testing L+N to E.
    Am testing all circuit neutrals plus this circuit's line to earth though - but why would that give such low readings?
     
  3. peter palmer

    peter palmer Well-Known Member

    You are testing all the lives of every other circuit as well
     
  4. Beacon

    Beacon New Member

    Reviving an oldish thread, advice please on insulation testing.
    I have been through a CU and got acceptable results for majority of circuits.
    2 circuits, one a final and the other a ring final.
    Following earlier advice I fully disconnected these circuits, line/cpc/neutral and tested cps to live+neutral, hoping to deal with any devices still connected.
    Both circuits still give very low results <0.5Mohms. Both circuits function just fine and are in a house approximately 30 years old. Last periodic test was 10 years ago, the results of which are not available.

    Thoughts? Help? Thanks.
     
  5. Bazza-spark

    Bazza-spark Well-Known Member

    Are you sure everything is unplugged? It happened to me and I found multiway extension blocks with LED's and surge protectors hidden in wardrobes, behind beds etc.

    Kind regards
     
  6. Beacon

    Beacon New Member

    Thanks Bazza - Had a good go around and thought I'd found everything, but you can never be sure I guess.
    Wouldn't testing L+N to E get around this?
     
  7. Bazza-spark

    Bazza-spark Well-Known Member

    Not with filters. They have capacitors connected to earth.

    Kind regards
     
  8. peter palmer

    peter palmer Well-Known Member

    Easiest way to check is low ohms test live to neutral, any sort of reading and there is something plugged in.
     
  9. Beacon

    Beacon New Member

    Sorry for late reply - thanks to all for their input. My conclusion is that testing is the worst part of the job!
     

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