SCR, that is very interesting, but what worries me is that there is no locking mechanism, and relays are consumable items. So, if mains live was connected to the load, but solar neutral was welded shut, I'd have mains live running through my building, going through my inverter's neutral! I have no idea what the effects of that are, but it's certainly not ideal. Infact, wouldn't that trip my house RCD?