Juniper MX2010 Hardware Manual page 328

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.
NOTE: The DC PDMs in slots PDM0/Input0, PDM2/Input0, (and PDM1/Input1, and
PDM3/Input1 on MX2020 Routers) can be powered by dedicated power feeds derived
from feed A, or feed B. This configuration provides the commonly deployed A/B feed
redundancy for the system to balance the power draw. For information about connecting
to DC power sources, see MX2000 Router DC Power Subsystem Electrical Specifications.
NOTE: Make sure the amperage switch is set to 60 A or 80 A to match the DC circuit
input feed.
5. Route the positive and negative DC power cables through the plastic cable restraint cover. Make sure
that the cable does not touch or obstruct any router components.
6. Verify that the power cabling is correct, that the cables are not touching, and that they do not block
access to router components or drape where people could trip on them.
7. Attach the power cable to the DC power source.
8. Switch on the dedicated customer site circuit breaker.
9. On each of the DC power input sources, switch the DC circuit breaker to the center position before
moving it to the ON position.
NOTE: The circuit breaker may bounce back to the off position if you move the breaker
too quickly.
10. Verify that the –48V LED on the PDM is lit steadily.
You must ensure that power connections maintain the proper
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