Juniper MX960 Hardware Manual page 359

CAUTION:
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.
6. Remove the nut and washer from each of the terminal studs. (Use a 7/16-in. [11 mm] nut driver or
socket wrench.)
7. Secure each power cable lug to the terminal studs, first with the split washer, then with the nut (see
Figure 116 on page 345). 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.)
a. Secure each positive (+) DC source power cable lug to the RTN (return) terminal.
b. Secure each negative (–) DC source power cable lug to the –48V (input) terminal.
CAUTION:
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:
supply is 58 lb-in. (6.5 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 slots PEM0 and PEM1 must be powered by dedicated
power feeds derived from feed A, and the DC power supplies in slots 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.
8. Loosen the captive screw on the cable restraint on the lower edge of the power supply faceplate.
You must ensure that power connections maintain the proper
Ensure that each power cable lug seats flush against the surface of
The maximum torque rating of the terminal studs on the DC power
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