The UCS 5108 blade chassis comes with options of up to four power supply units. Each is a single phase unit and provides 2,500 watts. Depending on the total number of power supplies in the chassis and input power sources, UCS 5108 can be configured into the following three modes:
Power supply units installed in the system provide adequate power. A power supply failure results in a chassis failure. Load is evenly distributed among power supplies; however, there is no power redundancy.
In this mode, at least one extra power supply unit is available in the system in addition to the units that are required for providing the power required for the chassis to be operational. The extra power supply unit is in standby mode and the load is evenly distributed among the operational power supply units. In case of single power supply failure, standby power will replace the failed power supply immediately.
In this mode, all the four power supply units must be available in the system and power should be supplied from two different power sources. Power supply units must be configured in pairs. Units 1 and 2 form one pair, and 3 and 4 form the second pair. Ideally, separate physical power cabling from two independent utility grids is recommended to feed each pair of power supply. In case one power source fails, the remaining power supply units on the other circuit continue to provide power to the system.
The power connector inside the UCS blade server chassis is IEC 60320 C19. The connector on the other side of the power cable varies according to the country-specific electrical standards.
Note
More information regarding power and environmental requirements is available at http://www.cisco.com/en/US/docs/unified_computing/ucs/hw/site_prep/guide/siteprep_tech_specs.html#wp1064498.