Technical data

Field Replaceable Unit Removal and Replacement
Removing Power from the Shelf
Chapter 1
29
Removing Power from the Shelf
In a telecommunications environment, the 14-Slot Shelf is typically installed with a separate High
Availability (HA) four-domain input power supply configuration to each of the 14-Slot Shelf Power Entry
Modules (PEMs). In this configuration input power can be removed from either or both PEMs on the Shelf, as
required.
WARNING WARNING: High Voltage. Follow appropriate safety precautions to avoid electrical shock.
There are no system power controls on the 14-Slot Shelf. System power (-48 VDC from multiple
power domains) is applied by an external power source at all times unless disabled or
disconnected at the source.
To remove all input power from the 14-Slot Shelf, disable or disconnect all circuit breakers on all external
power supplies for both PEMs.