The 3000 W AC-input power supply designed for the Cisco Catalyst 6509-NEB-A Switch, called the WS-CAC-3000W, requires single-phase source AC. Source AC can be out of phase between multiple power supplies or multiple AC-power plugs on the same power supply because all AC power supply inputs are isolated. We offer pre-owned and new WS-CAC-3000W power supplies to enhance your network.