Power Supplies - Juniper QFX5100 Hardware Manual

QFX5100 Switch Hardware Guide
176
WARNING: Ensure that the power cables do not block access to device
components or drape where people can trip on them.
Connect each power supply to the power sources. Secure power source cables to the
7.
power supplies by screwing the ring lugs attached to the cables to the appropriate
terminals by using the screw from the terminals (see
Figure 59 on page 177 ).
The QFX5100 is designed to operate with a DC power supply that has a single,
non-redundant, feed input. For source redundancy, two DC power supplies must be
installed in QFX5100; connect source (A) to one power supply and connect source
(B) to the second power supply. This configuration provides the commonly deployed
A/B feed redundancy for the system.
The terminal block of the power supply has four terminals labeled V+, V+, V–, and V–
for connecting DC power source cables labeled positive (+) and negative (–). The V+
terminals are shunted internally together, as are the V- terminals.
CAUTION: The connection between each power source and power supply
must include a circuit breaker.
Do not connect two sources to a single power supply because doing so
can potentially cause circulating current in feed wires whenever there is
any difference in the voltage of the two sources.
NOTE: For QFX5100-96S installations using battery backup, a single 15 A
circuit breaker is recommended.
Secure the ring lug of the positive (+) DC power source cable to the V+ terminal
a.
on the DC power supply.
Secure the ring lug of the negative (–) DC power source cable to the V– terminal
b.
on the DC power supply.
Tighten the screws on the power supply terminals until snug using the screwdriver.
c.
Do not overtighten—apply between 5 in-lb (0.56 Nm) and 6 in-lb (0.68 Nm) of
torque to the screws.
Figure 58 on page 177 and
Copyright © 2016, Juniper Networks, Inc.