Installing a DC Power Supply

To install a DC power supply (see Figure 3):

1. Ensure that the voltage across the DC power source cable leads is 0 V and that there is no chance that the cable leads might become active during installation.
2. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist and connect the strap to one of the ESD points on the chassis. For more information about ESD, see Preventing Electrostatic Discharge Damage.
3. Switch the circuit breaker on the power supply faceplate to the OFF position O.
4. Using both hands, slide the power supply straight into the chassis until the power supply is fully seated in the chassis slot. The power supply faceplate should be flush with any adjacent power supply faceplates.
5. Tighten the captive screws on the lower edge of the power supply faceplate.
6. Remove the clear plastic cover protecting the terminal studs on the faceplate.
7. Remove the nuts and washers from the terminal studs.
8. Secure each power cable lug to the terminal studs, first with the washer, then with the nut. Apply between 23 lb-in. (2.6 Nm) and 25 lb-in. (2.8 Nm) of torque to each nut. (see Figure 4).
   1. Attach the positive (+) DC source power cable lug to the RTN (return) terminal.
   2. Attach the negative (–) DC source power cable lug to the –48V (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. The color coding used by the external DC power source at your site determines the color coding for the leads on the power cables that attach to the terminal studs on each power supply.

   Note: For the SRX 5600 services gateway, the DC power supply in PEM0 and PEM1 must be powered by dedicated power feeds derived from feed A, and the DC power supply in PEM2 and PEM3 must be powered by dedicated power feeds derived from feed B. This configuration provides the commonly deployed A/B feed redundancy for the system.

   Note: For information about connecting to DC power sources, see the SRX 5600 Services Gateway Hardware Guide.

9. Replace the clear plastic cover over the terminal studs on the faceplate.
10. Route the power cables along the cable restraint towards the left or right corner of the chassis. If needed to hold the power cables in place, thread plastic cable ties, which you must provide, through the openings on the cable restraint.
11. Verify that the power cabling is correct, that the cables are not touching or blocking access to services gateway components, and that they do not drape where people could trip on them.
12. Verify that the INPUT OK LED on the power supply is lit green.
13. Switch the circuit breaker on the power supply to the ON position — and observe the status LEDs on the power supply faceplate. If the power supply is correctly installed and functioning normally, the PWR OK, BRKR ON, and INPUT OK LEDs light green steadily.

    Note: If more than one power supply is being installed, turn on all power supplies at the same time.

Note: An SCB must be present for the PWR OK LED to go on.

Figure 3: Installing a DC Power Supply

Figure 4: Connecting DC Power