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What earthing arrangement is this?

Former Community Member
Former Community Member
The supply is from a private transformer in a four core cable 3ph + n. The cable armour is earthed and connected to the MET. However there is also a green and yellow cable connected to the neutral terminal at the main isolator going back to a the transformer casing. The transformer is only 5 or 6 metres away. I think this must have been intended to make it a tncs supply but seems to me to just create parallel neutral conductors. Or is it tn-s-c-s?  I have only been able to go off visual inspection because I could not disconnect the supply..
Parents

  • mapj1:

    If it is pre 1980 Print a card in red ink on white background, or later than that black ink on yellow background like the service cut-out stickers you almost never see.




    for the door to the equipment, that says any one of these ,
    2810bb5e0303cfe5c12d40fb67abeae6-huge-earth_labels.png
    and watch all contractors copy it faithfully onto the test sheets from now on. The reports will be consistent at least.

     







    I like that, shame im not certain if its option 2 or 3!

Reply

  • mapj1:

    If it is pre 1980 Print a card in red ink on white background, or later than that black ink on yellow background like the service cut-out stickers you almost never see.




    for the door to the equipment, that says any one of these ,
    2810bb5e0303cfe5c12d40fb67abeae6-huge-earth_labels.png
    and watch all contractors copy it faithfully onto the test sheets from now on. The reports will be consistent at least.

     







    I like that, shame im not certain if its option 2 or 3!

Children
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