[RWebb]

ok, this is definitely the cable to the 240V heater - white/black/gnd - so single phase (???)

the feed to the 110V outlet comes in from the top (not the bottom) is silver, not white like this Romex

now, I do NOT want to trust the moron PO's choice of cable size so what type of cable do I need to buy for a 220V run to a Cadet heat that is rated for 2.25 kW output?

the cable to the heater is LOT more flexible and smaller than the feed cable running to the wire nut jct. they made