Juniper EX8208 Hardware Manual page 71

Figure 13: DC Power Supply
NOTE: A 2000 W DC power supply requires a dedicated 60 A circuit breaker for each input DC
feed.
A 3000 W DC power supply requires a dedicated 100 A circuit breaker for each input DC feed.
Each DC power supply connects to the backplane in an EX8208 switch and to the midplane in an EX8216
switch. The backplane in an EX8208 switch and the midplane in an EX8216 switch distribute the output
power produced by the power supplies to different switch components. Each DC power supply provides
power to all the components in the switch.
The output of each 2000 W DC power supply is 52 VDC. The output power is 2000 W.
The output of each 3000 W DC power supply is 52 VDC. The output power is 3000 W.
A DC power supply works with only one input DC feed connected. It is able to deliver the full output
power to all chassis components with only one DC feed connected.
Each DC power supply has its own fan and is cooled by its own internal cooling system. The airflow is from
the front of the power supply to the back. Hot air exhausts from the rear of the chassis.
The minimum power configuration required by an EX8200 switch is an N+1 power configuration. In an
N+1 power configuration, if one power supply fails or is removed, the remaining power supplies continue
to supply power for the system without interruption.
The configuration type of the switch and the input voltage determine the number of power supplies needed
(N) for a switch. You must install an additional power supply to meet the required N+1 power redundancy
configuration. The DC power supplies each provide independent A and B power feeds, so that dual power
feed redundancy is available even in an N+1 configuration. See
for details about different EX8208 switch configurations. See EX8216 Switch Configurations for details
about different EX8216 switch configurations.
"EX8208 Switch Configurations" on page 27
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