Cisco Catalyst 4500 Series - Special Considerations for the 1400 W DC Power Supply

14-21
Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 14 Environmental Monitoring and Power Management
Power Management
Power supplies currently available : 2
Power Summary Maximum
(in Watts) Used Available
---------------------- ---- ---------
System Power (12V) 1323 2646
Inline Power (-50V) 0 6022
Backplane Power (3.3V) 40 67
---------------------- ---- ---------
Total 1363 (not to exceed Total Maximum Available = 7412)
Special Considerations for the 1400 W DC Power Supply
Caution Do not mix the 1400 W DC power supply with any other power supply, even for a hot swap or other
short-term emergency. Doing so can seriously damage your switch.
Keep in mind the following guidelines when using a 1400 W DC power supply with your Catalyst 4500
series switch:
• The 1400 W DC power supply works with a variety of DC sources. The DC input can vary from
300 W to 7500 W. Refer to the power supply documentation for additional information.
• The supervisor engine cannot detect the DC source plugged into the 1400 W DC power supply. If
you are using the 1400 W DC power supply, use the power dc input command to set the DC input
power. For more information on this command, see the “Configuring the DC Input for a Power
Supply” section on page 14-21.
• The software automatically adjusts between system power (for modules, backplane, and fans) and
PoE. Although PoE is 96 percent efficient, system power has only 75 percent efficiency. For
example, each 120 W of system power requires 160 W from the DC input. This requirement is
reflected in the “Power Used” column of the output for the show power available command.
• The 1400 W DC power supply has a separate power on or off switch for PoE. The power supply fan
status and main power supply status are tied together. If either of them fails, both the power supply
and its fan report as bad/off. You should verify that the main power is on before turning on the power
for the inline switch. In addition, you should verify that the power for the inline switch is off before
turning off the main power.
Configuring the DC Input for a Power Supply
To configure the DC input power for the 1400 W DC power supply or a power shelf, perform this task:
The same configuration is applied to both power slots. For example, if you set the dc power input to
1000 W, the switch expects 1000 W as the external DC source for both slot 1and slot 2 (if present).
The following example shows how to set the external DC power source to 1000 W:
Switch# configure terminal
Switch (config)# power dc input 1000
Command Purpose
Step 1
Switch# configure terminal
Enters configuration mode.
Step 2
Switch(config)# power dc input watts
Sets the capacity of the DC input source.
Step 3
Switch(config)# end
Exits configuration mode.