Cisco Nexus 9504 Hardware Installation Manual page 19

Preparing the Site
To determine the maximum amount of power that can be consumed by this switch when fully loaded with components,
add the maximum power consumed by two supervisor A modules (2 x 80 W = 160 W), two system controllers (2 x 25
W = 50 W), four 48-port 1- and 10-Gigabit BASE-T I/O modules (4 x 550 W = 2200 W), six fabric modules (6 x 125
W = 750 W), and three fan trays (3 x 135 W = 405 W). The total is 3565 W.
Step 2 Determine the number of power supplies needed for the available power requirement by dividing the power requirement
amount (see Step 1) by the output wattage of the power supplies installed in the switch.
For 3-kW power supplies, round up a fractional result to the nearest ones digit to determine the number of power supplies
needed.
For example, if you are installing a switch with 3-kW power supplies and have a maximum consumption of 3565 W,
you need two power supplies (3565 W / 3000 W = 1.18 [rounded up to 2 power supplies]) to operate the switch and its
modules.
Step 3 Select one of the following power modes to determine the number of additional power supplies required for reserve
power:
• Combined power—Do not add any power supplies to the number of power supplies calculated for the available
power in Step 2. This power mode does not provide power redundancy, so no extra power supplies are needed.
• Power supply redundancy (n+1 redundancy)—Add one power supply (reserve power supply) that can output as
much power as the most powerful power supply used for active power. This form of power redundancy provides
a reserve power supply that can replace any active power supply that goes offline.
• Input source redundancy (grid or n+n redundancy)—Add enough power supplies (reserve power supplies) to at
least equal the total output of the active power supplies (the number of power supplies calculated in Step 2).
Typically, you double the number of power supplies. You must plan for a second power source for the reserve
power supplies. For example, if you calculate that you need two 3-kW power supplies for 6 kW of available power,
you need another two 3-kW power supplies for 6 kW of reserve power (for a total of four 3-kW power supplies
used for available and reserve power).
Step 4
Be sure that the power source circuits are dedicated to the switch and not to other electrical equipment.
For combined power mode (no power redundancy) or power supply (n+1) redundancy, you need only one dedicated
circuit. For input-source (grid or n+n) redundancy, you must have two dedicated power circuits, with each circuit powering
half of the 3-kW power supplies. The requirements for each circuit are listed in the following table.
Power Supply
3-kW AC power supply (N9K-PAC-3000W-B)
Step 5 Plan the placement of the input power receptacles within reach of the power cables used for each power supply (see the
following table for the maximum distances).
Typically, power receptacles are placed on the rack with the switch.
Power Supply
All AC power supplies
Number of Circuits
1 (power supply redundancy or no
power redundancy)
2 (input-source redundancy)
Maximum Distance Between Receptacle and Power Supply
12 feet (3.5 m)
Cisco Nexus 9504 NX-OS Mode Switch Hardware Installation Guide
Planning for Power Requirements
Requirement for Each
Circuit
16 A at 210 to 240 VAC
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