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Commando sockets & RCD

Apostolos

Good afternoon

I have 2 questions around commando sockets & RCD protection that may have already been answered so in this case please do forgive my ignorance

1. I have a commercial kitchen full of 32A TPN commando sockets for various equipment

Do these commando sockets count as regular sockets that would need RCD as per BS7671?

I know that regulations now do not accept risk assessments on this so it boils down to whether a commando socket is treated like a regular socket

2. I have an IT room where for each cabinet I have been asked to provide a 16A SPN commando socket

This is a single phase so RCBOs are readily available.

However, this is a comms cabinet that will be fed and I remember from older engineers that we do not want RCD elements on the supply of IT equipment.

So, again the question remains if the commando is treated like a regular socket and if so how would the IT equipment be combined with an RCD?

Any views are appreciated on both

Thanks

  • +1

    The 32 amp sockets in a kitchen would almost certainly need RCD protection if installed today. In the case of an existing installation that was made before RCDs were required, then opinions differ as to whether retrofitting same is required.

    In the case of racks of IT equipment, then the absence of RCD protection seems to be generally accepted. In such circumstances I would hope for duplicated earth connections. This may be achieved by earthing each rack in the usual way AND ALSO providing a second earth connection to each rack, independent of the earth core in the flex from the 16 amp plug.

  • 0

    Do these commando sockets count as regular sockets that would need RCD as per BS7671?

    The requirement for additional protection by 30mA RCD applies to all sockets generally rated ≤32A - so yes 'commando' sockets would be included

    I know that regulations now do not accept risk assessments

    The risk assessment option hasn't entirely disappeared - it's still an option where the socket is not liable to be used by ordinary persons/children/disabled - so if a socket is in a location where it's intended to be only used by to skilled or instructed persons (chances are it can be arranged for IT staff to be instructed) then that's still a possibility. A rack of IT equipment may well have a standing leakage current of over 9mA - which would preclude the use of a 30mA RCD.

       - Andy.

  • 0 in reply to broadgage

    In the kitchen we will probably go with an RCD incomer however this means one out....all out which is not...ideal..

  • 0

    Sections 8.2.3  and 4.9 of the 9th Ed (2022) of IET Guidance Note 5 Protection against electric shock provides updated guidance relating to Regulation 411.3.3.

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