I doubt that HVAC systems have the complexity at the access panel that a multi-phased CNC machine would have.
AC systems have what three tap selections for voltage offset? Oh wait, you are the idiot that says they don't read past the panel tag.
Regardless, people. If you are hooking up a high power requisite device (machine), and it contains multiple power taps for VOLTAGE SELECTION on its termination panel, then the person doing the hooking up is responsible to make sure that he hooked up the right wire to the right terminal. If he does not have the experience in the industry to perform that task, he has no business claiming to be an electrician.
PERIOD!