Hi, I’d like to switch to a tankless water heater to recover a closet in my (small, limited-storage, old) house, and I’ll need to have an electrical outlet added. Unfortunately the existing house wiring has no grounds, so GFCI receptacles provide 3-prong outlets where necessary. Would that count as “properly grounded” for installing a tankless water heater, or do we need to have a whole new circuit added with a real ground?