Juniper Networks MX480 - Manual (Page 261)

3. Verify that the INPUT OK LED on the power supply is not lit.
4. Remove the power cable from the external DC power source.
5. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect
the strap to one of the ESD points on the chassis.
6. Move the DC circuit breaker on the power supply faceplate to the off ( O )position.
7. Remove the clear plastic cover protecting the terminal studs on the faceplate.
8. Remove the nut and washer from each of the terminal studs. (Use a 7/16-in.
[11 mm] nut driver or socket wrench.)
9. Remove the cable lug from the terminal studs.
10. Remove the power cable from the cable restraint, and then carefully move the cable
out of the way.
Connecting an MX480 DC Power Supply Cable
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.
To connect a power cable for a DC power supply:
1. Locate a replacement power cable that meets the specifications defined in “DC Power
Cable Specifications for the MX480 Router” on page 304 .
2. Verify that a licensed electrician has attached a cable lug to the replacement power
cable.
3. Verify that the INPUT OK LED is off.
4. Secure the power cable lug to the terminal studs, first with the flat 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 123 on page 238 ). Do not overtighten the nut. (Use a 7/16-in. [11 mm]
torque-controlled driver or socket wrench.)
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.
237 Copyright © 2013, Juniper Networks, Inc.
Chapter 14: Replacing MX480 Hardware Components