I'm going to be wiring a 50A 240V circuit to a shed through an MF conduit. There will be about 3 feet of conduit connecting to a subpanel and it will remain above ground. I know the neutral wire must be white or grey and the ground _must be green, yellow-green or bare. Can I use 2 black conductors for the hot wires or must they be black and red?
This is for a location in the United States.