Quote Originally Posted by performance View Post
Rivets is right. Its single,split phase...But AC guy is wrong. There is 2 phase systems out there, albeit they are older and fading away in this country. I think the last two phase systems may be in NY state.
Mark, if the secondary of the step-down transformer is center-tapped, it produces 2 branches each 180 degrees out of phase with each other when referenced to the center tap..

So while we call it single phase when running line-line, it is technically a 2-phase system when run line-neutral.

You guys can call it anything you want, but it behaves exactly as I have described it.