I live in New England. (It is also ok to use 2 conductor w/Grnd #10 sheathed cable which comes one black, one white, one bare for a 240VAC, 1phase load.) Some 240VAC appliances like this one, come with blk, wht, grnd. it is because of manufacturers fault...the screw for the cover at the back was touching the wires that goes to the thermostat switch...you can see that in the picture...i called the manufacturer and they were not of anyhelp... I waited a long time to have this installed as my contractor got sick in the coldest part of this winter. This is a heating unit and any heating unit improperly operated can burn things down.The thermostat at its lowest setting keeps the room about 40deg F with it 30's outside.