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Regulation stating a type AC RCD can not be upstream from a type A RCD

Alan B

Hi

I found an EV charger today with built in type A RCD + RDC-DD connected to a type AC RCD in the consumer unit, the AC RCD is also protecting 3 other circuits including sockets. I know this is incorrect because the type AC RCD could be blinded by DC currents, but I am struggling to find a regulation to reference when providing information to the customer?

Thanks

Alan

Parents
  • 0

    It's all very well arguing the technicalities, but that horse has bolted and the stable door is also well and truly bolted as well, so we are left in the position of having to comply with the new Wiring Regulations. 

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  • 0

    It's all very well arguing the technicalities, but that horse has bolted and the stable door is also well and truly bolted as well, so we are left in the position of having to comply with the new Wiring Regulations. 

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  • 0 in reply to Sparkingchip

    Possibly Andy, but corrections are possible, although they can cause red faces! However I think it is important that the situation is fully understood by the industry, and the reasons need to be correct. We do tend to have a situation where IEC (or Cenelec or whatever) has suggested a regulation, but it is important to know exactly why and to be able to explain to customers why the item they bought last year is no longer satisfactory. If the reasons were as seems to be suggested, I think type As would not be suitable either as the alleged DC leakage current is in no way controlled, except by a potential fault resistance (its DC)!

  • 0 in reply to Sparkingchip

    IEC 62350 referenced in note 2  is probably documents the guidance on cascading RCD's but unfortunately I don't have access, I suspect this is the case for most electricians.

  • 0 in reply to Alan B
    Alan B said:
    IEC 62350 referenced in note 2  is probably documents the guidance on cascading RCD's but unfortunately I don't have access, I suspect this is the case for most electricians.

    Not in terms of whether a Type AC can be used upstream of a Type A or Type B, or whether a Type A can be used upstream of a Type B.

    Whilst Type B are mentioned, note that this Technical Report (it's not a full IEC standard) was published before Type B and Type F RCDs fully appeared in the product standards (BS EN 62423), and so Type B's only get a cursory glancing mention, and Type F's are not mentioned at all.

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