Juniper EX6210 Complete Hardware Manual page 203

Copyright © 2014, Juniper Networks, Inc.
Remove the washers and nuts from each DC power input terminal, using the
4.
3/8-in. (9.5 mm) nut driver or socket wrench to loosen the nuts. Leave the bolts
installed on the input terminals.
Ensure that the power source circuit breaker is open so that the voltage across the
5.
DC power source cable leads is 0 V and that the cable leads do not become active
while you are connecting DC power.
Verify that the DC power cables are correctly labeled before making connections to
6.
the power supply. In a typical power distribution scheme where the return is connected
to chassis ground at the battery plant, you can use the multimeter to verify the
resistance of the and
–
The cable with very high resistance (indicating an open circuit) to chassis ground
is negative (–) and must be installed on the
The cable with very low resistance (indicating a closed circuit) to chassis ground is
positive (+) and must be installed on the
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 DC
power input terminals on each power supply.
Install each power cable lug on the DC power input terminal, securing it first with a
7.
locking washer, then with the nut (see
CAUTION: Apply maximum of 56.4 in.-lb (6.4 Nm) of torque to tighten
each nut—do not overtighten. Applying excessive force might damage the
terminal studs or power supply.
a. Secure each positive (+) DC source power cable lug to the
input terminal.
b. Secure each negative (–) DC source power cable lug to the
input terminal.
NOTE: If the optional power cord tray is installed, you can thread the DC
power cables through the power cord tray.
DC cables to chassis ground:
+
– (input) DC power input terminal.
(return) DC power input terminal.
+
Figure 69 on page
Chapter 10: Connecting the Switch
and to indicate
(+) (–)
184).
+ (return) DC power
(input) DC power
–
183