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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

    Just thinking aloud - say we had something with an internal d.c. supply, not galvanically isolated from the mains ('cos it's cheaper) that could under certain fault conditions send a limited current (a few 10s of mA perhaps) to PE - I've got in mind something like an LED bulkhead with an LED strip stuck to an Earthed steel dish.

    Do I have in mind (much simplified) something like:

    That of itself wouldn't be hazardous, but it seems like it could disable an AC type RCD, so loosing additional protection not just from that circuit but any other circuits that rely on the same RCD (as in split load CUs), and the first fault could persist indefinitely. It'd still need a 2nd fault for danger, but where we have additional protection we'd expect something rather better than just the old-fashioned two-faults to danger, which we're not really getting any more.

       - Andy.

  • 0 in reply to AJJewsbury

     Primary simple, reliable, protection is afforded by good solid earthing and bonding in association with overcurrent protective devices. (Excepting TT installations).

    Z.

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  • 0 in reply to AJJewsbury

     Primary simple, reliable, protection is afforded by good solid earthing and bonding in association with overcurrent protective devices. (Excepting TT installations).

    Z.

Children
  • 0 in reply to Zoomup
    Zoomup said:
    Primary simple, reliable, protection is afforded by good solid earthing and bonding in association with overcurrent protective devices. (Excepting TT installations).

    But that doesn't offer additional protection only ADS for a fault of negligible impedance.

  • 0 in reply to gkenyon

    That's exactly it. The new electronic blinding appliances are dangerous. Then we have to be careful with the use of appliances and D.I.Y. work at home. If we can't rely upon R.C.D.s to be totally bombproof and effective under all reasonable conditions of use times are bad..  And run all cables in earthed steel conduit.

  • 0 in reply to Zoomup

    So show me one of these, i haven't seen one.

  • 0 in reply to David Stone

    One of what?

    Z.

  • 0 in reply to Zoomup

    A properly working appliance that prevents a type AC operating properly, Do you normally test RCDs with full load current? Not that that should matter, but it does if you claim that VSDs or whatever prevent proper operation.

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