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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.
  • 0
    Didn't we have a similar discussion recently? I thought that there was another thread too.
  • 0
    IIRC, any green/yellow cable linking the two systems should be marked blue at the ends to indicate that it may be carrying diverted neutral current.


  • 0
    broadgage:

    IIRC, any green/yellow cable linking the two systems should be marked blue at the ends to indicate that it may be carrying diverted neutral current.


     


    Using that logic, you'd have to mark up your main earthing conductor and main protective equipotential bonding conductors in absolutely every PME system in the same way! Because it can just happen anyway.


  • 0
    IIRC, any green/yellow cable linking the two systems should be marked blue at the ends to indicate that it may be carrying diverted neutral current.

    I thought that was (one option) specifically for a PEN conductor (the other being a blue conductor marked G/Y at terminations).


       - Andy.
  • 0
    Also every TNS system might be very TNC-S like because of nearby jointing or simply because in a nearby property someone might have inadvertently or not have linked them anyway

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