Equipment is designed to operate +/- 10% of the nameplate rating. In the case of taps like what happened here, the taps are supposed to be set by theelectrician to fall within the 10% range. With the taps set at 220v the CNC machine was good to operate from 218v to 242v. As the power installer, it was the electrician's responsibility to verify the voltage coming into the building and adjust the taps on the machine accordingly. He was paid to correctly hook up power to the machine and failed to do so.