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Overload protection

If you have a 32 amp feeder feeding 4x 6 amps circuits feed in parallel is there something in the regs that states the cable between the 32amp fuses dosmt have to be rated for 32 amps as long as It meets certain condition? my thinking was as its limited to 6 amps upstream it’s unlikely to get overloaded.

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  • Does 433.3.3 apply?

    More likely 433.2.2 I think - we're not omitting overload protection, just positioning it downstream of the conductor it's protecting.

    The regs are worded in terms of a single protective device, but I reckon 4off 6A devices are pretty equivalent to one 24A device as far as overload is concerned.

    Note that this approach only applies to overload protection - other overcurrent protection (faults) need to have protective devices placed upstream - but they of course may have significantly higher rating than the conductors and still be effective (the magnitude of the fault current and disconnection times being suitable co-ordinated with the device and conductor).

       - Andy.

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  • Does 433.3.3 apply?

    More likely 433.2.2 I think - we're not omitting overload protection, just positioning it downstream of the conductor it's protecting.

    The regs are worded in terms of a single protective device, but I reckon 4off 6A devices are pretty equivalent to one 24A device as far as overload is concerned.

    Note that this approach only applies to overload protection - other overcurrent protection (faults) need to have protective devices placed upstream - but they of course may have significantly higher rating than the conductors and still be effective (the magnitude of the fault current and disconnection times being suitable co-ordinated with the device and conductor).

       - Andy.

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