I will install a long buried cable to a subpanel in a remote barn. Online wire-size calculators (including this one at AskMeDIY), require me to input if my circuit is 120 or 240 V, and this parameter produces different wire-size results. MY QUESTION: My cable will have two hot leads (each 120, allowing 240 V at barn), but my subpanel will also be used for single 120 V lighting circuits. Do I input 120 V or 240 V in wire-size calculators? Thank you, Tom.