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30mA RCDs for sockets - AMD2

As you many (or may not) have noticed, AMD2 deletes the option to omit 30mA RCD protection for socket outlets (by documented risk assessment). So then ALL sockets rated ≤32A will need to be on a 30mA RCD.


This strikes me as unhelpful for some situations - e.g. feeds to server racks in data centres where the cumulative protective conductor currents will likely nuisance trip a 30mA device and hard-wiring instead using plugs & sockets is undesirable as non-skilled persons (electrically) are likely to need to be able to disconnect/reconnect the supplies to racks (sometimes under 'duress' conditions).


There are probably other situations too - I've seen 16A sockets used to feed lights high up in major railway station canopies (presumably so the fittings can be readily disconnected and brought to ground level for maintenance) - where I guess the risk of loss of lighting far outweighs the risk from shock.


OK we possibly get around the letter of the regs by hard-wiring to a short length of flex and having a connector (trailing socket) on the end of that (thus side-stepping the definition of a socket outlet which has to be connected to fixed wiring) - but that hardly seems to be in the spirit of the regs, nor necessarily a good technical solution where a fixed socket would have been the better solution.


Further thoughts?


  - Andy.
Parents
  • Or in the case of the compressor, perhaps an inrush limiter.

    The bigger problem I see is racks of radio or IT equipment with EMC filters.

    I fear it may encourage folk to try and reduce the amount of filtering, which with my EMC hat on is a very bad thing, already the standards are nothing like  tight enough to allow co-location of kit that only just pass the immunity specs along side things that only just meet the emissions spec - things work because good designs have 10-20dB of margin between the minimum spec and the performance (or are not co-located).

    If we did not have to consider L-N reversal in product design, then one could have larger capacitors L-N and N-E and omit the one wired L-E, but given the European influence I do not see that.

    If we had 3 phase appliances at lower currents, then the leakage from 3 identical filters each leaking from one phase L-E does more or less cancel, but 3 phase 16A connectors is not the UK way, and a supply suitable for that not always available anyway.

      I'd prefer and predict a lot of 63 A connectors with 2.5mm cables and similar cunning, as folk are not keen to put 'does not meet BS7671 by design' in the paperwork.

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  • Or in the case of the compressor, perhaps an inrush limiter.

    The bigger problem I see is racks of radio or IT equipment with EMC filters.

    I fear it may encourage folk to try and reduce the amount of filtering, which with my EMC hat on is a very bad thing, already the standards are nothing like  tight enough to allow co-location of kit that only just pass the immunity specs along side things that only just meet the emissions spec - things work because good designs have 10-20dB of margin between the minimum spec and the performance (or are not co-located).

    If we did not have to consider L-N reversal in product design, then one could have larger capacitors L-N and N-E and omit the one wired L-E, but given the European influence I do not see that.

    If we had 3 phase appliances at lower currents, then the leakage from 3 identical filters each leaking from one phase L-E does more or less cancel, but 3 phase 16A connectors is not the UK way, and a supply suitable for that not always available anyway.

      I'd prefer and predict a lot of 63 A connectors with 2.5mm cables and similar cunning, as folk are not keen to put 'does not meet BS7671 by design' in the paperwork.

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