Hi, I am trying to hook up a 400w quad tap ballast and am wondering what two wires to use for the 240v hook up. their is one marked 240 and the rest are marked 120, 208,277,com. whitch wires do i hook up to for the 240v. residential home shop application single phase.

 

240 goes to L1, COM goes to L2 - or the other way around.
Put insulating wire nuts on all of the other unused leads.
Make certain that you connect the supply ground wire to the ground of the light fixture.