Airflow Requirements - Cisco Nexus 93120TX Installation Manual

Airflow Requirements

• Two 930-W DC power supplies
• Any combination of the above power supplies
Note For n+1 redundancy, you must provide power to both power supplies. For n+n redundancy, you must
provide power to both power supplies and each power supply must be connected to a different power
source.
The power supplies are rated to output up to either 1200 W (AC power supplies) or 930 W (DC power supplies)
to the switch, but the switch requires less than those amounts of power from the power supply. To operate
the switch you must provision enough power from the power source to cover the requirements of both the
switch and a power supply. Typically, this switch and a power supply require about 542 W of power input
from the power source, but you must provision as much as 948 W power input from the power source to cover
peak demand.
To minimize the possibility of circuit failure, make sure that each power-source circuit used by the switch is
dedicated to the switch.
For the AC power cables that you can use with this switch, see
Note
For DC power cables, the recommended wire gauge is 8 AWG and the minimum wire gauge is 10 AWG.
Airflow Requirements
The switch is designed to be positioned with its ports in either the front or the rear of the rack depending on
your cabling and maintenance requirements. Depending on which side of the switch faces the cold aisle, you
must have fan and power supply modules that move the coolant air from the cold aisle to the hot aisle in one
of the following ways:
• Port-side exhaust airflow—Coolant air enters the chassis through the fan and power supply modules in
• Port-side intake airflow—Coolant air enters the chassis through the port end in the cold aisle and exhausts
You can identify the airflow direction of each fan and power supply module by its coloring as follows:
• Blue coloring indicates port-side exhaust airflow.
• Burgundy coloring indicates port-side intake airflow.
• Green coloring indicates port-side intake airflow on DC power supplies.
Note To prevent the switch from overheating and shutting down, you must position the air intake for the switch
in a cold aisle, and all of the fan and power supply modules must have the same direction of airflow (even
if their coloring is different).
Cisco Nexus 93120TX NX-OS Mode Switch Hardware Installation Guide
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the cold aisle and exhausts through the port end of the chassis in the hot aisle.
through the fan and power supply modules in the hot aisle.
Preparing the Site
Power Cord Specifications, on page 48.