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Reverse Polarity

bakey1959

Has anyone encountered a reverse polarity single phase PME supply to a house? If so, how did it happen and how was it detected?

I am intrigued to how you would discover it by measuring L-N, L-E, and N-E at the incoming side of the Main Switch, as the Earthing conductor would be connected to the Line at the cut-out and give 0V, the same as if it were correctly wired and you were measuring N-E?

I cannot get my head around how you would detect the issue.... maybe I will set it up on an empty standalone C/U and see what I get?

Parents
  • 0

    Surely if you earth the incoming live there will be a big flash and lots of smoke as the earth lead burns up also after all you would get current of hundreds of amps just briefly until your earthing and or bonding conductors burn up. I cannot imagine it's a situation that could last long

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  • 0

    Surely if you earth the incoming live there will be a big flash and lots of smoke as the earth lead burns up also after all you would get current of hundreds of amps just briefly until your earthing and or bonding conductors burn up. I cannot imagine it's a situation that could last long

Children
  • 0 in reply to Kelly Marie Angel

    I did consider that, but then also tried to envisage an extraneous conductive part free situation, perhaps a house with no metallic services... and in this situation could a PME Line/ PEN reversal remain on the installation supply, prior to installation energisation?

  • 0 in reply to Kelly Marie Angel

    Depends what you mean by Earth - short to the DNO's Earth terminal, yes. Connect to a local electrode - probably not - more likely a few amps flow....

    In the OP's suggested case it's only a reversal of the L and PEN conductors - no short as such (unless there's bonding to extraneous-conductive-parts that are metallic though to another installation, where they're bonded to a correctly polarised supply from the same transformer, in which case, yes flash and bang again).

        - Andy.

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