Install DC Power Supplies

QFX10008 power supplies are hot-insertable and are field-replaceable units (FRUs). You can install up to six power supplies in a QFX10008. The power supplies install in the rear of the chassis in the slots provided along the left side.

Caution: Do not mix AC and DC power supplies in the same chassis.

1. Before you install a DC power supply in the chassis, ensure that you have followed all safety warnings and cautions:

   Warning: Before performing DC power procedures, ensure that power is removed from the DC circuit. To ensure that all power is off, locate the circuit breaker on the panel board that services the DC circuit, switch the circuit breaker to the OFF position, and tape the switch handle of the circuit breaker in the OFF position.

   Caution: Before you connect power to the switch, a licensed electrician must attach a cable lug to the grounding and power cables that you supply. A cable with an incorrectly attached lug can damage the switch (for example, by causing a short circuit).

   Caution: To meet safety and electromagnetic interference (EMI) requirements and to ensure proper operation, you must connect QFX10008 switches to earth ground before you connect them to power. For installations that require a separate grounding conductor to the chassis, use the protective earthing terminal on the switch chassis to connect to earth ground. For instructions on connecting a QFX10008 switch to ground using a separate grounding conductor, see Ground the Chassis.

2. Ensure that you have the following parts and tools available to install a DC power supply in a QFX10008:
   • Electrostatic discharge (ESD) grounding strap
   • DC power source cables (not provided) with the cable lugs (provided) attached

     The provided terminal lugs in a QFX10008 are sized for 4 AWG (21.1 mm²) power source cables. The DC power source cables that you provide must be 4 AWG (21.1 mm²), minimum 60°C wire. We recommend that you install heat-shrink tubing insulation around the power cables and lugs.

   • 13/32 in. (10 mm) nut driver or socket wrench
   • Phillips (+) screwdrivers, numbers 1 and 2
   • Multimeter

To install a DC power supply in a QFX10008 (see Figure 24):

1. Attach the electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to the ESD point on the chassis. There is an ESD point located next to the protective earthing terminal and below PSU 5 on the rear panel .
2. Taking care not to touch power supply components, pins, leads, or solder connections, remove the power supply from its bag.
3. Peel back and remove the protective plastic wrap that covers all four sides of the power supply.
4. Ensure the power switch is set to the standby (O) position. This switch turns off the output voltage; it does not interrupt DC.
5. Remove the plastic cable cover from the DC power input terminals by using the Phillips (+) screwdriver, number 2, to loosen the screws.
6. Remove the nuts from each DC power input terminal, using the 13/32 in. (10 mm) nut driver or socket wrench to loosen the nuts.
7. Ensure that the power source circuit breaker is open so that the voltage across the DC power source cable leads is 0 V and that the cable leads do not become active while you are connecting DC power.
8. Verify that the DC power cables are correctly labeled before making connections to the power supply. In a typical power distribution scheme where the return is connected to chassis ground at the battery plant, you can use a multimeter to verify the resistance of the –48V and RTN DC cables to chassis ground:
   • The cable with very high resistance (indicating an open circuit) to chassis ground is negative (–) and will be installed on the –48V (input) DC power input terminal.
   • The cable with very low resistance (indicating a closed circuit) to chassis ground is positive (+) and will be installed on the RTN (return) DC power input terminal.

   Caution: You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity. There is no standard color coding for DC power cables.

9. Install each power cable lug on the DC power input terminal, securing it with the nut (see Figure 22). Apply between 24 in.-lb (2.7 Nm) and 25 in.-lb (2.8 Nm) of torque to each nut. [Use the 13/32 in. (10 mm) nut driver or socket wrench.]
   1. Secure each positive (+) DC source power cable lug to the RTN (return) DC power input terminal.
   2. Secure each negative (–) DC source power cable lug to the –48V (input) DC power input terminal.

   Each power supply has two independent sets of DC power input terminals (INPUT 1: RTN –48V/–60V: and INPUT 2: : RTN –48V/–60V). For feed redundancy, each power supply must be powered by dedicated power feeds derived from feed INPUT 1 and feed INPUT 2. This configuration provides the commonly deployed INPUT 1 / INPUT 2 feed redundancy for the switch.

   Figure 22: Connecting the DC Power Supply Cables to a QFX10008

   
10. Install the plastic cable cover over each set of power cables by using the Phillips (+) screwdriver, number 2, to tighten the screw.
11. If the power supply slot on the chassis has a cover panel on it, insert your thumb and forefinger into the finger holes, squeeze, and pull the cover out of the slot. Save the cover panel for later use (see Figure 23).

    Figure 23: Removing the PSU Cover Panel

    
12. Unscrew the captive screw in the counterclockwise direction by using the Phillips (+) screwdriver, number 1.
13. Pull the captive screw away from the faceplate of the power supply to release the latch.

    Note: You can install the power supplies in any slot labeled PSU 0 through PSU 5 (top to bottom).

14. Using both hands, place the power supply in the power supply slot on the rear of the switch. Slide the power supply straight into the chassis until the power supply is fully seated in the slot. Ensure the power supply faceplate is flush with any adjacent power supply faceplates or power supply cover panels (see Figure 24).
15. Push the captive screw into the power supply faceplate. Ensure that the screw is seated inside the corresponding hole on the faceplate.
16. Tighten the captive screw by turning it clockwise by using the Phillips (+) screwdriver, number 1. When the screw is completely tight, the latch locks into the switch chassis.

    Figure 24: Installing a QFX10008 DC Power Supply

    

    1 — Source input 1 enable switch

    2 — Source input 2 enable switch

17. Warning: Ensure that the power cords do not block access to switch components or drape where people can trip on them.

18. Set the enable switches for input 1 and input 2 (see Figure 25).

    Set both enable switches to the | (on) position when using both source inputs. When not using source redundancy, set the unused source to the O (off) position. The LED turns red and indicates an error if a source input is not in use and the enable switch is | (on).

    Figure 25: Setting the Enable Switches for the Power Source

    

    1 — Source input 1

    2 — Source input 2

19. Verify that the input 1 and 2 LEDs on the power supply faceplate are lit and are on steadily.
20. Press the power switch to the on (|) position.