Sounds like a faulty wired breaker box. I've actually had this before. When I encountered it, I found out someone had taken 2 seperate 30 amp breakers and put the two sides of the "220" volt lines into them. The problem - both are on the same phase side. So it's not 220, it's 2 seperate 125 volt legs of the same phase. A 220-240 volt dual 30 amp breaker grabs both sides of the bus, thus giving 220 volt 2 phase. Either that, or something happened in the transformer on the supply side. I would call an electrician if you can't figure it out.