As far as I'm concerned we have: 120 208 240 277 480 However, I was once told that supply voltages has slowly been boosted over the years. I don't know if it's true, but it could explain some old motors with 440 volt ratings. Also, some older equipment seems to have 110 or 220 on the nameplates. And let's not forget that pesky 460 rating. Where in the world did that come from?
