Juniper EX4300 Hardware Manual page 212

EX4300 Switch Hardware Guide
190
CAUTION: You must ensure that power connections maintain the proper
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 DC
power input terminals on each power supply.
Ensure that the input circuit breaker is open so that the voltage across the DC power
3.
source cable leads is 0 V and that the cable leads will not become active while you
are connecting DC power.
NOTE: The V+ terminals are referred to as +RTN and V– terminals are
referred to as –48 V in
and "DC Power Electrical Safety Guidelines for Switches" on page
Ensure that the power supplies are fully inserted in the chassis.
4.
Remove the terminal block cover. The terminal block cover is a piece of clear plastic
5.
that snaps into place over the terminal block.
Remove the screws on the terminals by using the screwdriver. Save the screws.
6.
WARNING: Ensure that the power cables do not block access to switch
components or drape where people can trip on them.
NOTE: The DC power supply has five terminals, two positive terminals
labeled V+ and two negative terminals labeled V–, for connecting the
power supply to a dedicated DC power source by using the DC power
source cables labeled positive (+) and negative (–), and one terminal for
connecting the power supply to earth ground (see
The V+ terminals are shunted internally together, as are the V– terminals
to provide parallel current path.
Connect one end of the grounding cable to a proper earth ground, such as the rack in
7.
which the switch is mounted.
Place the grounding lug attached to the grounding cable over the earthing terminal
8.
on the DC power supply.
"DC Power Wiring Sequence Warning" on page 321
Copyright © 2017, Juniper Networks, Inc.
316.
Figure 51 on page 192).