The 6000-watt (W) power supply for the Cisco Catalyst 6500 Series chassis is a dual AC input power supply. When both inputs are at high line (220 VAC nominal voltage) then the output is 6000W. When both inputs are active but at least one is operating at low line (110 VAC nominal voltage), or a single input is active and running from a high line (220 VAC nominal voltage) source, the unit is capable of providing 2900W output power.All Cisco Catalyst 6500 Series chassis hold up to two load-sharing, fault-tolerant, hot-swappable power supplies. Only one supply is required to operate a fully loaded chassis. If a second supply is installed, it operates in a load-sharing capacity. The power supplies are hot swappable - a failed power supply can be removed without powering off the system.