I have been doing electrical work sense I was an 8 year old kid helping by BIL on side jobs. I have worked as an electrician many times as a journeyman but the is something I still don't understand and I have asked general foremans and superintendtants and they can't give me an answer. 120 volts is single phase and that is simple enough to understand and 3 phase is simple enough to understand, but why is 240 volts 2 phase?????????? The way I look at it is. Can anyone make me understand this problem. It ranks right up there with where is the end of the universe at. There has to be an end, but at the same time there can't be, because somewhere has to exist on the other side of the end.