I have red/black/white cable coming into barn to breaker box from main panel at house. With a tester to neutral bar each leg reads 120v and if two hot legs are tested, 240v.
I have a 20 amp breaker that goes to a timer that control a series of lights. When I turn on breaker for the lights, which are wired correctly, one hot leg drops to 0v and the other leg reads 240v when tested to neutral bar.
I have another breaker to outlet plug that reads fine until I energize the breaker for timer then it too loses voltage because of timer motor somehow shifting all volts to other leg. I've replaced timer with new brand new timer / replaced breaker with new one. I've even run extension cord to lights directly and bypassing breaker box and they work fine if timer/breaker box is bypassed.
Any suggestions where to look?