No main breaker panels @ Home Depot?

[kalakoa]

Backfeed the panel through a 30A breaker. Panel should include a MAIN sticker which can be used to label this breaker. If inverter is single-phase, use a short piece of large-gauge wire (eg, #6 or #4) to bridge the L1/L2 lugs so that all breaker positions are energized.

I'm partial to the plastic GE load center because it's non-conductive and doesn't rust.