Nortel Networks 8000 Series - Manual (Page 23)

8000 Series DC power supplies 23
Installing a DC Power Supply in an Ethernet Routing Switch 8000 Series Chassis
If either the individual or combined power for the components exceed the
output power rating of the power supply, you need to add at least one more
power supply to your configuration.
3 Consider your redundant power supply needs. If one power supply satisfies
your system power-consumption needs, a second power supply provides
redundancy. If two power supplies satisfy your system power consumption
needs, a third power supply provides redundancy.
Redundant power configuration
If a chassis has a redundant power configuration and one power supply fails, the
chassis continues to operate with no interruption of service. The chassis will
continue to supply the same module output power with the remaining power
supplies. A trap and syslog message will indicate that the configuration is
non-redundant. Nortel recommends that you operate the Ethernet Routing Switch
8600 system in a redundant configuration at all times to ensure maximum network
up time.
If a chassis has the minimum power supply configuration and one power supply
fails, the system loses power and network connectivity.
Note: Nortel recommends that you install each power supply on its own
dedicated branch circuit. This ensures that a fault on another branch
circuit doesn’t cascade onto other branch circuits.
A redundant power supply provides protection against the failure of
another power supply in the system.