Install a DC Power Supply

Up to four 1,600 watt power supply modules can be installed in the Extreme 9920 chassis. Each power supply is self enclosed and vents directly to the rear of the chassis. If the chassis has more than two power supplies installed, power supplies are hot-swappable. The power supply slots are situated in the four contiguous slots starting from the left-hand side to the bottom and the rear of the chassis. They are numbered PSU 1 through PSU 4.

Note

Do not remove the cover from the fifth, or last, power supply slot on the far right to the bottom and the rear of the chassis.

The DC power supply does not ship installed and must be ordered separately. A DC power cord is provided with the DC power supply.

Caution

Make sure that the DC power supply circuit is not overloaded. Use proper overcurrent protection, such as a circuit breaker, to prevent overcurrent conditions. You can use up to a 36-Amp or greater breaker.

Use the following tasks to install a DC power supply in a switch:

Make sure you have the tools and materials you need. See Required Tools and Materials for Installing a DC Power Supply.
Insert the power supply into the switch. See Install the DC Power Supply.
Connect the power supply to the DC source voltage. See Connect a DC Power Supply to the Source Voltage.

Required Tools and Materials for Installing a DC Power Supply

You need the following tools and materials to install or remove a DC power supply.

Connection hardware appropriate to the installation site:
- Hardware for connecting the power wires to the DC source.
- Hardware for connecting the ground wire to the site grounding point.
ESD-preventive wrist strap.
Thermal protective gloves (for removal of a warm power supply).

Install the DC Power Supply

Note

Before installing a DC power supply, verify that the airflow direction for the power supply is the same as the airflow direction of the installed fan modules in the switch.

To install the power supply, follow these steps:

Caution

The handle on the power supply is not designed to be used to lift or carry the power supply or the switch to which it is attached.

Attach an ESD-preventive wrist strap to your bare wrist and connect the metal end to an appropriate ground point on the rack.
Identify the power supply slot in the chassis to install the power supply module, and remove the filler panel, if necessary.
Verify that the power supply is right side up by orienting the power supply so that the green tabbed release lever is on the right-hand side.
Slide the power supply into the power supply slot, until the release lever locks the power supply in place and the power supply is properly seated, as shown in Inserting a DC power supply into the chassis.
Inserting a DC power supply into the chassis

Caution
Do not slam the power supply into the switch.
To install additional power supplies, repeat the procedure.

When you are finished, use the DC power input cable that is provided with the DC power supply to ground the power supply and connect the power supply to the power source. Follow the instructions in Connect a DC Power Supply to the Source Voltage.

Connect a DC Power Supply to the Source Voltage

The DC power connection at your facility must be made by a qualified electrician, following these instructions.

Warning

Always make sure that the DC circuit is de-energized before connecting or disconnecting the DC power cables on the DC power supply.

Caution

Provide proper connection and strain relief on the DC power cables in accordance with all local and national electrical codes.

Verify that the DC circuit is de-energized.
Attach an ESD-preventive wrist strap to your bare wrist and connect the metal end to an appropriate ground point on the rack.
Position the DC power cable connector so that the wide, flat side is closest to the fan, as shown in Connecting the DC power cord. The DC power cable connector can only connect to the power supply one way.
Warning
These instructions are only for one version of the cable. Ensure that the polarity markings on the cable match the polarity markings on the 9920 and the polarity markings on the DC power source.

Connecting the DC power cord
Tighten the two thumb screws to secure the DC power connector in place.
The installation electrician connects the other end of the power cord to the building power system.
Warning
Before installing, be sure to connect the chassis ground wire before you connect any power cables.

Warning
Before removing, be sure to disconnect the ground wire after you disconnect all power cables.
1. Connect the fork terminal of the ground wire to a known reliable earth ground point at your site.
  DC power cable terminals
2. Connect the fork terminal of the positive power cable to the positive terminal of the DC power source, and connect the fork terminal of the negative power cable to the negative terminal of the DC power source.
Repeat these steps for each power supply.

Leave the ESD strap permanently connected to the rack, so that the strap is always available when you need to handle ESD-sensitive components.

After connecting the DC power supply to the power source, the DC circuit can be energized. Follow the instructions in the topic Turn on the Extreme 9920 to energize the DC circuit. The LED light for the DC power supply unit is solid green when connected and operating normally.