Juniper T640 Hardware Manual page 387

Copyright © 2017, Juniper Networks, Inc.
Make sure that the voltage across the DC power source cable leads is 0 V and that
1.
there is no chance that the cables might become active during installation.
CAUTION: You must ensure that power connections maintain the proper
polarity. The power source cables might be labeled
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.
Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect
2.
the strap to one of the ESD points on the chassis.
Switch the circuit breakers on the power supply faceplate to the off position (
3.
Using both hands, slide the power supply into the chassis until you feel resistance.
4.
Twist the ejector handles at the upper corners of the power supply faceplate clockwise
5.
until they stop.
Tighten the captive screws at the lower corners of the power supply faceplate to
6.
secure the power supply in the chassis.
Remove the clear plastic cover protecting the terminal studs on the faceplate.
7.
Remove the nut and washer from each power terminal stud. If no washers and nuts
8.
are already installed, they should be in the accessory box.
Secure the cable lug on the DC power cable to the terminal stud, first with a washer,
9.
then with a nut (see Figure 174 on page
to tighten the nut (see Figure 173 on page
25 lb-in. (2.8 Nm) of torque to each nut:
Secure each positive (+) DC source power cable lug to a
a.
Secure each negative (–) DC source power cable lug to a
b.
NOTE: All inputs on the two-input 160-A DC power supply in slot
must be powered by dedicated power feeds derived from feed A, and all
inputs on the two-input 160-A DC power supply in slot
powered by dedicated power feeds derived from feed B. This configuration
provides the commonly deployed A/B feed redundancy for the system.
Chapter 29: Replacing Power System Components
(+)
356). Use a 7/16-in. (11 mm) nut driver or wrench
355). Apply between 23 lb-in. (2.6 Nm) and
RTN
–48V
and (–) to indicate
).
O
(return) terminal.
(input) terminal.
PEM0
PEM1 must be
353