Specifications

7-18 Cisco MGX 8220 Reference, Release 4.1
Connecting Power for AC Systems
Connecting Power for AC Systems
This sections describes how to connect AC power to the MGX 8220 shelf.
AC Input Power
The AC power assembly can be configured with either a single primary input AC source or optional
primary and secondary (redundant) input AC sources. AC power is supplied through connectors on
the rear panel.
Available Power
The AC power assembly holds up to six independent 875W power supplies each of which supplies
power to a common output bus. Power is then available for MGX 8220 shelves through connectors
on the rear panel.
The number of power supplies that are configured in the assembly depends upon the number of
MGX 8220 shelves that have to be supported. The maximum number of MGX 8220 shelves that can
be supported by a single AC power assembly is four.
In a fully loaded configuration each MGX 8220 shelf requires 500 watts. Therefore, a power
assembly equipped with three power supplies, totaling 2625W, can supply enough power for a four
shelf rack. A power assembly equipped with four power supplies, totaling 3500W, provides enough
power for a four shelf rack even in the event of a single power supply failure. More power supplies
provide even more protection in the event of multiple power supply failures.
Monitoring Power Supply Status
In addition to supplying power, each power supply provides a signal that indicates the status of the
power supply.
Rear Panel Connectors
The rear panel has:
• Primary AC input connector and an optional secondary AC input connector.
• Group of four output connectors on the right (looking towards the rear panel), each of which can
be used to connect to an MGX 8220 shelf. Connectors 1A-3A provide power and power supply
monitoring. Connector 4A provides power only.
• Group of three output connectors on the left (looking towards the rear panel), each of which can
be used to connect to an MGX 8220 shelf to provide power supply monitoring.
Referring to Figure7-13, power is available at each of the four connectors on the right of the rear
panel. A cable from any of these four connectors can be connected to any shelf in the rack.