120/240V Single Phase 3 Wire Explanation And Demonstration
The split phase system in America is a bit confusing but actually it's kind of ingenious in the sense that no wire has more than a 120 volt potential to ground. But it turns out there is more than meets the eye - the nuetral line actually carries any current not equal between the two phases back to the transformer - and if it's disconnected only the lowest amperage of the two phases will work. Fascinating stuff.