Installing an MX480 DC High-Capacity Power Supply

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. Move the power switch on the power supply faceplate to the off (O) position.
3. 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 faceplate or blank installed in the power supply slot.
4. Using a screwdriver, loosen the captive screw holding the metal cover over the input mode switch. Rotate the metal cover away from the input mode switch to expose the switch.
5. Check the setting of the input mode switch. Use a sharp, nonconductive object to slide the switch to the desired position. Set the input mode switch to position 0 for 60-A input and position 1 for 70-A input. This setting is used by the power management software and needs to be set before on the power supply. See Figure 1.

   Figure 1: MX480 DC High-Capacity Power Supply Input Mode Switch

   
6. Rotate the metal cover over the input mode switch, and use a screwdriver to tighten the captive screw.
7. Tighten the captive screws on the lower edge of the power supply faceplate.
8. Remove the clear plastic cover protecting the terminal studs on the faceplate.
9. Remove the nut and washer from each of the terminal studs.
10. Secure each power cable lug to the terminal studs, first with the flat washer, then with the split washer, and then with the nut (see Figure 2). Apply between 23 lb-in. (2.6 Nm) and 25 lb-in. (2.8 Nm) of torque to each nut. Do not overtighten the nut. (Use a 7/16-in. [11 mm] torque-controlled driver or socket wrench.)
    1. Secure the positive (+) DC source power cable lug to the RTN (return) terminal.
    2. Secure the negative (–) DC source power cable lug to the –48V (input) terminal.

    Caution: Ensure that each power cable lug seats flush against the surface of the terminal block as you are tightening the nuts. Ensure that each nut is properly threaded onto the terminal stud. The nut should be able to spin freely with your fingers when it is first placed onto the terminal stud. Applying installation torque to the nut when improperly threaded may result in damage to the terminal stud.

    Caution: The maximum torque rating of the terminal studs on the DC power supply is 36 lb-in. (4.0 Nm). The terminal studs may be damaged if excessive torque is applied. Use only a torque-controlled driver or socket wrench to tighten nuts on the DC power supply terminal studs.

    Note: The DC power supplies in PEM0 and PEM1 must be powered by dedicated power feeds derived from feed A, and the DC power supplies 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.

11. Replace the clear plastic cover over the terminal studs on the faceplate.
12. Route the power cables along the cable restraint toward 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.
13. Verify that the power cabling is correct, that the cables are not touching or blocking access to router components, and that they do not drape where people could trip on them.
14. Switch on the dedicated customer site circuit breakers. Follow your site's procedures for safety and ESD.
15. Verify that the INPUT OK LED on the power supply is lit green.
16. On each of the DC power supplies, turn the power switch to the on (—) position.
17. 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.

Figure 2: Connecting DC Power to the Router