The application surprises me just a bit.
First, the pumps seem just a tad large for a home. Maybe there's a significant lift or something.
Otherwise ... is it really a requirement for a generator hook-up? Or just a requirement for back-up power?
I ask because I have seen pre-packaged battery systems for such pumps. Set on the floor near the pumps - plug pumps into the unit - plug the unit into house power - done.
Might be worth a visit to the plumbing house.
