7-4
Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
Chapter7 Environmental Monitoring and Power Management
Power Management
These power supplies are incompatible with Catalyst 4500 series switches. Since Power over Ethernet
(PoE) is not supported on the Catalyst 4948 switch, only a limited wattage is needed. (For information
on PoE, see Chapter 8, “Configuring Power over Ethernet.”) When you insert power supplies in your
switch, the EEPROM on the power supplies can be read by the system software even if the supply is not
powered on. You may mix AC and DC power supplies.

Power Management Modes

The Catalyst 4948 switches support the redundant power management mode. In this mode, if both power
supplies are operating normally, each provides from 20/80 to 45/55 percent of the total system power
requirements at all times. If one power supply fails, the other unit in creases power to 100 percent of the
total power requirement.
Power Management for the Catalyst 4500 Series Switches
This section includes the following subsections:
•Supported Power Supplies, page 7-4
•Power Management Modes, page 7-5
•Selecting a Power Management Mode, page 7-6
•Power Management Limitations in Catalyst 4500 Series Switches, page 7-6
•Available Power for Catalyst 4500 Series Switches Power Supplies, page 7-12
•Special Considerations for the 1400 W DC Power Supply, page 7-12
•Special Considerations for the 1400 W DC SP Triple Input Power Supply, page 7-14

Supported Power Supplies

You can select from several different power supplies to ensure that you have enough power for the
modules installed in your switch. The Catalyst 4500 series switches support the following power
supplies:
•Fixed Wattage—These power supplies always deliver a fixed amount of PoE and system power.
–
1000 W AC—Supports up to 1000 W of system power. (Not recommended on the Catalyst
4510R switch, PoE not supported)
–
1400 W AC—Supports up to 1400 W system power. (PoE not supported)
–
2800 W AC—Supports up to 1400 W of system power and up to 1400 W of PoE.
•Variable Wattage—These power supplies automatically adjust the wattage to accommodate PoE and
system power requirements.
–
1300 W AC—Supports up to 1000 W of system power and 800 W of PoE, limited to a total of
1300 W.
–
1400 W DC—Supports up to 1400 W of system power and variable amounts of PoE, depending
on the input feed to the power supply. See “Special Considerations for the 1400 W DC Power
Supply” section on page 7-12 for more information.