Cisco GSR12/60 - 12012 Router -AnyLAN, SONET/SDH Installation And Configuration Manual page 264

Removing and Replacing a DC-Input Power Supply
Step 9
Figure 7-11
Circuit breaker
alarm terminal
block
7-24 Cisco 12012 Gigabit Switch Router Installation and Configuration Guide
Disconnect the source DC power cable leads from the power supply lugs in the
following order: negative (–), positive (+), and ground. (See Figure 7-11.)
Disconnecting the DC-Input Power Supply
– + Ground
Source DC
power cable