Recently a friend and I have been doing some remodeling on my garage. We decided to hookup a 240 sub panel from the main house. We strung some jacketed #8 wire in conduit from the main panel to the new sub. There are three wires in the jacket: a white one, a black one and a bare copper one. The power is coming from the main panel from a two pole 50 amp breaker. We used the white and black wires as the two hots and lugged it to the two buses in the sub for 240v. It works but as I was drifting off to sleep just now I realized I don’t have a neutral wire in the Sub panel. Is this an accident waiting to happen? What should I do?