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Connecting two earthing systems - PME on both - any implications of this?

Former Community Member
Former Community Member
Question out of theorotical interest, can you connect the earthing systems of two PME supplies to achieve equipotential bonding between the two electrical supoplies or devices they power?


What are the pro's and con's of this? I understand the implications of PEN faults which might make the earth have touch voltage but if there is equipotential bonding between two earth systems would the earth fault current (earth which now carries live voltage from neutral) not flow through to the earth of the other PME supply?


Appreciate your thoughts.
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  • 0
    If it exceeds 100A on the phase the mains incoming or service fuse should blow anyway hence preventing any risk to people?

    A fuse won't provide any protection against a broken PEN situation as the fuse will only be in the line condutor, never the PEN. The problem is that the PEN could end up carrying the aggregate N current of several installations, even though no single installation is overloaded (and that's the case whether the PEN is broken or not).


    Likewise an RCBO won't offer any protection at all from a broken PEN situation.

      - Andy.
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  • 0
    If it exceeds 100A on the phase the mains incoming or service fuse should blow anyway hence preventing any risk to people?

    A fuse won't provide any protection against a broken PEN situation as the fuse will only be in the line condutor, never the PEN. The problem is that the PEN could end up carrying the aggregate N current of several installations, even though no single installation is overloaded (and that's the case whether the PEN is broken or not).


    Likewise an RCBO won't offer any protection at all from a broken PEN situation.

      - Andy.
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