Juniper MX240 - UPGRADING Manual page 20

Upgrading MX240, MX480, and MX960 3D Universal Edge Router Power Supplies and Fan Trays
20
CAUTION: The maximum torque rating of the terminal studs on the DC
power supply is 36 lb-in. (4.0 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.
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.
NOTE: The DC power supplies in
dedicated power feeds derived from feed
in PEM2 and
from feed . This configuration provides the commonly deployed
B
redundancy for the system.
NOTE: For information about connecting to DC power sources, see DC
Power Supply Electrical Specifications for the MX480 Router.
Replace the clear plastic cover over the terminal studs on the faceplate.
9.
Route the power cables along the cable restraint toward the left or right corner of the
10.
chassis. If needed to hold the power cables in place, thread plastic cable ties, which
you must provide, through the openings on the cable restraint.
Verify that the power cabling is correct, that the cables are not touching or blocking
11.
access to router components, and that they do not drape where people could trip on
them.
Switch on the dedicated customer site circuit breakers. Follow your site's procedures
12.
for safety and ESD.
Verify that the
INPUT OK
On each of the DC power supplies, switch the DC circuit breaker to the center position
13.
before moving it to the on (
NOTE: The circuit breaker may bounce back to the off (
move the breaker too quickly.
PEM0
PEM3 must be powered by dedicated power feeds derived
LED on the power supply is lit green.
) position.
—
and to indicate
(+) (–)
and must be powered by
PEM1
, and the DC power supplies
A
A/B
O ) position if you
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feed