It’s worth noting that this is talking about plug in solar, so would be at standard mains voltage.

Thats fair.

At least in the UK, they tend to run 3 phase to a road, but only a single phase goes into a given house. You need to get a special hook up to get 3 phase to a domestic premise, and they don’t like doing it.

TIL about the UK electrical system. Thanks!

I’m at the edge of my knowledge but that sounds like it matches the USA system (for the number of phases).