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Achieving acceptable Zs on a final circuit.

geov

Sorry, brain fog….existing three phase final circuit protected by a 63a type c mcb. Zs is well in excess of the tabulated value. Is it acceptable practice to put a BS88 fuse after the mcb (next to the db) to increase the maximum permitted Zs?

Parents
  • 0

    yes - if the fuse provides closer protection than the MCB- how is the cable supplying the 63A protected ?

    That will need at least 5 seconds cover...

    Mike.

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  • 0

    yes - if the fuse provides closer protection than the MCB- how is the cable supplying the 63A protected ?

    That will need at least 5 seconds cover...

    Mike.

Children
  • +1 in reply to mapj1

    Mcb is in the db. Thinking is to feed out to a fused disconnector immediately then out to the 63amp socket. Run is approx 45m. Using the mcb alone, Zs is way over.

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