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> Like, I understand we have the technology to monitor if grid disappears and self-disable, and a lot of hard-wired rooftop solar does that, but unsure if any s
by drcongo 3y ago
> Like, I understand we have the technology to monitor if grid disappears and self-disable, and a lot of hard-wired rooftop solar does that, but unsure if any soft-wired units have been approved.
Would you mind explaining this sentence? I know very little about these things but I'd like to, are you saying that rooftop solar switches itself off if there's no grid power? And if so, why?
- ragebol 3y agoYes, typically rooftop solar doesn't output when the grid is down. If the inverter doesn't get an AC sinus at 60 or 50 Hz, it won't do anything by default. Some systems can, in a so called 'island mode'. But this is so that they don't supply power when eg an electrician flips a breaker to safely do work. Then better not have the system still energized by solar... I guess the risk with smaller, plug in systems is that they're simpler without such precautions? And you would have 2 live prongs sticking out, which would be bad of course
- drcongo 3y agoAhhh, thank you, that totally makes sense now.
- bombcar 3y agoThere’s a lot of intelligence in a transfer switch that allows island mode - because it has to generate a sine wave when no utility one is present and sync back up with it when one returns. The cheapest ones just cut power when the sine is lost and then make their own, and cut power when they see it return and then sync.
- Scoundreller 3y agoThe much cheaper and covers many/most use cases alternative would be a unit that disconnects anything on-grid, and has some in-unit/on-unit sockets you can use during grid-fail at point of device or run extension cords to.