This is probably not it, but worth checking. Where I worked a couple of years ago, we kept have squirrels go up on the power lines and bar-b-q themselves and that took a leg of our three phase out. One day it only a certain leg out and left two on and the Haas Mini-mill had power but would not fire up. We didn't notice what it was untill we found some office lights out.
Probably not it but check your breakers and make sure you have all three legs at the machine.
Mike
Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28