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Restaurant Kitchen & 3-Phase Oven RCDs

Apostolos
Good morning.

I have a restaurant where according to the kitchen specialist's design we are feeding some 3-phase combi ovens (25Amps) though 32A three phase isolators in series with a 3phase 32A bayonet plugs & sockets.

Cabling in all cases will be SWA/LSF cable.

According to BS7671:2018 / 411.3.3 this is a socket outlet not exceeding 32A and therefor it shall need a three phase RCD 30mA.

Is there any escape from the RCDs in this occasion?

I know that in the past the limit used to be 20A sockets (now it is 32A) and that if it was used for a specific purpose machinery like in this case it could be excluded.

Has this been removed now? I cannot find anywhere the exclusion for special purpose sockets so I guess it has been removed.

Also the fact that we are going to an isolator first does it make any difference?

Thanks
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    and that if it was used for a specific purpose machinery like in this case it could be excluded.

    Has this been removed now? I cannot find anywhere the exclusion for special purpose sockets so I guess it has been removed.



    It's changed bit is still there in a way - there is still an option to omit 30mA RCD protection for a socket, but you need to be able to justify its omission and record that in writing - i.e. produce a documented risk assessment.


    3phase 32A bayonet plugs & sockets.



    I'm not sure what you mean by these (bayonet plugs remind me of the plugs that went into BC lampholders - but no way are they 32A let alone 3 phase!) I'm guessing at a US style rotoloc kind of thing. It's worth checking as if it really should be classed as say an appliance connector it might not fall within the definition of a socket so might give you an easy answer to your problem.


    The other approach is to forget the plug & socket arrangement and just hard-wire it. I can't imagine that a 17kW oven is going to be exactly portable.


      - Andy.
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  • 0

    and that if it was used for a specific purpose machinery like in this case it could be excluded.

    Has this been removed now? I cannot find anywhere the exclusion for special purpose sockets so I guess it has been removed.



    It's changed bit is still there in a way - there is still an option to omit 30mA RCD protection for a socket, but you need to be able to justify its omission and record that in writing - i.e. produce a documented risk assessment.


    3phase 32A bayonet plugs & sockets.



    I'm not sure what you mean by these (bayonet plugs remind me of the plugs that went into BC lampholders - but no way are they 32A let alone 3 phase!) I'm guessing at a US style rotoloc kind of thing. It's worth checking as if it really should be classed as say an appliance connector it might not fall within the definition of a socket so might give you an easy answer to your problem.


    The other approach is to forget the plug & socket arrangement and just hard-wire it. I can't imagine that a 17kW oven is going to be exactly portable.


      - Andy.
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