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Overload protection downstream of inverter on off grid solar pv system

MikeG

I'm looking at 230vac distribution system downstream of 10 KW PV Inverter. System is off grid with storage battery and I'm just involved at present in the ac distribution system for a commercial application

Prospective fault current therefore about 40A but normal circuit breakers or RCBO's cannot provide ADS within 0.4 or 5 Secs. I'm thinking that this situation must arise in every domestic application where a solar pv system integrates with an existing domestic wiring system so there must be a simple solution.

I have no previous experience of Solar and inverter driven supplies so probably missing something obvious so for this of us in this situation any help from the more experienced would be very helpful. 

  • in reply to AJJewsbury
    AJJewsbury said:
    So, if I've understood it correctly, we need only worry about devices marked "E2" or "E3" (as the other types are OK for "indirect contact" protection (i.e in the case of L-PE faults)) and those seem to be limited by note b to "Only devices integrated in one unit with a socket-outlet or designed exclusively for being associated locally with a socket outlet in a same mounting box." - so that makes me think of what we know in the UK as BS 7288 socket RCDs (or perhaps those industrial enclosures that have a modular DIN rail enclosure above a BS 4343 (as was) socket outlet).

    The ambiguous area ... which is also drawn out in the BEAMA Bulletin if I remember correctly, is that some devices intended for use in CUs and DBs are marked E3. The BEAMA Bulletin explains why this might happen.

    So, yes, I guess E1 or no marking are apparently OK for ADS without further enquiry, but E2 or E3 should not be selected to provide ADS, unless further due diligence is undertaken with the manufacturer.

    The Bulletin also tells us what's happening in the future with the newer standards, to avoid this uncertainty.

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