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Advice on coding dual (RCD) Residual Current Device board

Newfutile

A colleague of mine had come across a dual (RCD) Residual Current Device board with no spd,a solar pv system and a car charger.

this was installed around 2 years ago when built from new.

my understanding is that the evse cant be on a shared rcd neither can the solar.they are both type A rcd and the evse seems to have pen fault and dc protection built in.

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    To code something on an EICR I think you need to be able to refer back to a specific BS 7671 regulation.

    As far as I can see there's no requirement for a dedicated RCD for PV systems in section 712 (please do correct me if I've missed something!) - so the general requirements for a parallel generator apply - 551.7.1 (ii) demands DP switching (which your RCCB presumably provides, unlike some RCBOs) - but otherwise there doesn't seem to be a requirement for it not to be shared with other circuits (by disconnecting the N, in theory at least, the risk of shock to Earth is mitigated for all the downstream circuits even if a L-N voltage remains). Some guidance may well go beyond that, but I think that's difficult to justify as a code on a BS 7671 EICR. A note perhaps.

    Arguably the "protected individually" requirement for a a EV point applies to the charging point outlet, rather than the circuit that supplies the EVSE. If the charge point includes an RCD (or equivalent functionality) then I can see a point of view that the requirement is satisfied regardless of whether the supply circuit has no RCD at all or an  additional RCD that covers other circuits as well. There's nothing in the requirement to say there can't be extra RCDs upstream.

    You could argue about selectivity and the consequences of the operation of a single protective device, but for a domestic that'll be hard to prove I think.

       - Andy.

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    To code something on an EICR I think you need to be able to refer back to a specific BS 7671 regulation.

    As far as I can see there's no requirement for a dedicated RCD for PV systems in section 712 (please do correct me if I've missed something!) - so the general requirements for a parallel generator apply - 551.7.1 (ii) demands DP switching (which your RCCB presumably provides, unlike some RCBOs) - but otherwise there doesn't seem to be a requirement for it not to be shared with other circuits (by disconnecting the N, in theory at least, the risk of shock to Earth is mitigated for all the downstream circuits even if a L-N voltage remains). Some guidance may well go beyond that, but I think that's difficult to justify as a code on a BS 7671 EICR. A note perhaps.

    Arguably the "protected individually" requirement for a a EV point applies to the charging point outlet, rather than the circuit that supplies the EVSE. If the charge point includes an RCD (or equivalent functionality) then I can see a point of view that the requirement is satisfied regardless of whether the supply circuit has no RCD at all or an  additional RCD that covers other circuits as well. There's nothing in the requirement to say there can't be extra RCDs upstream.

    You could argue about selectivity and the consequences of the operation of a single protective device, but for a domestic that'll be hard to prove I think.

       - Andy.

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