I was given a 240 volt garage heater from a friend. When I built my garage I had the electrician run a wire so I could put a heater in down the road. He ran a orange wire with 4 wires in it black red white and ground. I went to make the connection in the heater today and the heater only has 2 blacks and a ground no white. So I know the blacks from the heater will get hooked to the black and red coming from the panel but what would I do with the white one. Any answer would be appreciated.
I assume you are in the USA. The heater is probably a pure 240V load with no need for the neutral (white) wire. you should simply cap the white wire with a wire nut and tuck it back into the electrical box.