Operation Manual - Critical Power Supplies

Separate bypass:if the separate bypass option is present, protective devices must be present on both the main power supply line and the bypassline.Note: the neutral of the input line and that of the bypass are commoned inside the equipment, so they must refer to the samepotential. If the two power supplies were different, an isolation transformer would have to be used on one of the inputs.UPS without any variation in neutral condition and with separate bypass inputconnected to independent power supply lineUPS with separate bypass input on independent power supply lineand with galvanic isolation at inputUPS with separate bypass input connected to independent power supply lineand with galvanic isolation at output