Replace an 800 W Internal DC Power Supply

The switches have two bays for hot-swappable power supplies. In a switch with a redundant power configuration, you can replace one power supply without powering down the switch.

Note

All installed power supplies must blow air in the same direction and must match the airflow direction of the installed fan modules.

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 30-Amp breaker.

Replace an 800 W DC Power Supply

Warning

Be sure to disconnect all power cables before you disconnect the chassis ground wire.

To replace an 800 W DC power supply, follow these steps:

Attach an ESD-preventive wrist strap to your bare wrist and connect the metal end to an appropriate ground point on the rack.
Note the orientation of the installed power supply, and the location of the latching tab at the right of the unit.
Push the latching tab toward the power supply handle and pull outward on the handle to disengage the power supply internal connectors, as shown in Remove an 800 W DC Power Supply.
Remove an 800 W DC Power Supply
Carefully slide the power supply the rest of the way out of the switch, as shown in Remove an 800 W DC Power Supply.
Caution
Power supplies can become very hot during operation. Wear thermal protective gloves when you remove a power supply from an operating switch.

Note
If you are not installing a replacement power supply, install a cover over the unoccupied power supply bay. Unoccupied bays must always be covered to maintain proper system ventilation and EMI levels.
Verify that the replacement power supply is oriented the same way as the unit you removed, and has the same airflow direction.
Carefully slide the power supply all the way into the power supply bay until the latch snaps into place, as shown in Replace an 800 W DC Power Supply.
Caution
Do not slam the power supply into the switch.

Replace an 800 W DC Power Supply
To install a second power supply, repeat the procedure.

When you are finished, use the provided 2 meter DC power input cable for the DC power supply to ground the power supply and connect the power supply to the power source.

Warning

Connect the chassis ground wire before you connect any power cables.

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.

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.
Connecting the DC Power Cord

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.

Connect the ring terminal of the yellow and green ground wire to a known reliable earth ground point at your site.

Use the following for the building wire harness:


Cable Connector	Wire Color		Ring Terminal
Pin 1	Black	-48V	Pin 3
Pin 2	Red	RTN	Pin 2
Pin 3	Yellow/Green	GRD	Pin 1

Connect the ring terminal of the red RTN power cable to the positive terminal of the DC power source, and connect the ring terminal of the black -48V 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.