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Wiring 133/230Y System

Former Community Member
Former Community Member
Is there anything I need to consider when designing and wiring for this type of system? TN-S without the neutral distributed.
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  • Former Community Member
    0 Former Community Member
    AJJewsbury:
    Do I use 0.8 seconds instead of 0.4 for my disconnection time?

    Table 41.1 puts the Uo boundary between 0.4s and 0.8s at 120V nominal - so as your Uo is 133V nominal (and TN), then by the book you should still be using 0.4s disconnection time for small final circuits (or 5s for socket circuits over 63A or other final circuits over 32A or any rating of distribution circuits).

       - Andy.





    I never understood that considering voltage at the fault point to remote earth will be lower.


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  • Former Community Member
    0 Former Community Member
    AJJewsbury:
    Do I use 0.8 seconds instead of 0.4 for my disconnection time?

    Table 41.1 puts the Uo boundary between 0.4s and 0.8s at 120V nominal - so as your Uo is 133V nominal (and TN), then by the book you should still be using 0.4s disconnection time for small final circuits (or 5s for socket circuits over 63A or other final circuits over 32A or any rating of distribution circuits).

       - Andy.





    I never understood that considering voltage at the fault point to remote earth will be lower.


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