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Choosing best rating circuit breaker to protect 16A commando socket

Alan B

I was installing a 16A commando socket today which I protected with a 30mA rcd followed by a 16A MCB.

Other breakers nearby were not heavily loaded so derating was not an issue. But if I say wanted to connect to a heavily loaded consumer unit my initial reaction would be to put in something like a 20A breaker and suitable cable.
But then I thought the socket and plugs are not fused and I have no control over the cable connected to the socket. Therefore do I have to assume I am protecting a cable that is only rated at 16A and never use a breaker with a rating that exceeds this?

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    If you have a circuit feeding one or more 16A sockets you can use a 20A breaker if you like - the OSG annex H3 used to mention this explicitly.

    H3
    Radial final circuits using 16 A socket- outlets complying with 85 EN 60309-2 (BS 4343)

    H3.1 General
    Where a radial circuit feeds equipment the maximum demand of which, having allowed for diversity, is known or estimated not to exceed the rating of the overcurrent protective device and in any event does not exceed 20 A, the number of socket-outlets is unlimited.

    H3.l Circuit protection

    The overcurrent protective device should have a rating not exceeding 20 A.

    And it was in the body of the older regs as well, though I cannot find a reference  quickly now. Actually you may like to know that the old BS4343 from which the commando plug derives its dimensions is pretty comfortably rated, and unless badly tarnished the 16A model is good for a quite a bit more than 20A without any distress. If only the authors of the 13A plug spec had included a similar slack, but they didn't, and it doesn't

    Mike

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  • 0

    If you have a circuit feeding one or more 16A sockets you can use a 20A breaker if you like - the OSG annex H3 used to mention this explicitly.

    H3
    Radial final circuits using 16 A socket- outlets complying with 85 EN 60309-2 (BS 4343)

    H3.1 General
    Where a radial circuit feeds equipment the maximum demand of which, having allowed for diversity, is known or estimated not to exceed the rating of the overcurrent protective device and in any event does not exceed 20 A, the number of socket-outlets is unlimited.

    H3.l Circuit protection

    The overcurrent protective device should have a rating not exceeding 20 A.

    And it was in the body of the older regs as well, though I cannot find a reference  quickly now. Actually you may like to know that the old BS4343 from which the commando plug derives its dimensions is pretty comfortably rated, and unless badly tarnished the 16A model is good for a quite a bit more than 20A without any distress. If only the authors of the 13A plug spec had included a similar slack, but they didn't, and it doesn't

    Mike

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