The sub panel in my shop is improperly wired (who, me? ) although there has been no problem so far. Lead-in wires are two #6, one black and one white plus a neutral coming off double 50A breakers. At the sub panel the black is tied to one leg and the white is on the other leg, so there is 240V between them. The neutral is tied to the neutral bar. The three wires go underground through about 200 ft. of about 1 3/8" ID PVC between the main panel and the sub. I have been told that the best thing to do is to put a single 50A breaker in the main panel and wire it as just a 120V feed, though I'd still prefer to have 240V somehow. I am not sure about fishing another wire through the PVC to provide proper 240V service, but really don't know. Any comments? Thanks, Bill

Your second wire, the white one, should also be black but other than that I don't see the problem. You still have your 220 cable, did I miss something?

Thanks for your reply. No, I missed something. I was wrong in saying that the return is a neutral, it is the bare ground wire which I'm sure is a no-no. And not being able to pull a true neutral easily, says 120V only? Bill