Juniper MX480 Hardware Manual page 396

NOTE: The DC power supplies in PEM0 and PEM1 must be powered by dedicated power
feeds derived from feed A, and the DC power supplies in PEM2 and PEM3 must be
powered by dedicated power feeds derived from feed B. This configuration provides the
commonly deployed A/B feed redundancy for the system.
NOTE: For information about connecting to DC power sources, see
Electrical Specifications for the MX480 Router" on page
9. Replace the clear plastic cover over the terminal studs on the faceplate.
10. Route the power cables along the cable restraint toward the left or right corner of the 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.
11. Verify that the power cabling is correct, that the cables are not touching or blocking access to router
components, and that they do not drape where people could trip on them.
12. Switch on the dedicated customer site circuit breakers. Follow your site's procedures for safety and
ESD.
Verify that the INPUT OK LED on the power supply is lit green.
13. On each of the DC power supplies, 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 (O) position if you move the breaker
too quickly.
Observe the status LEDs on the power supply faceplate. If the power supply is correctly installed and
functioning normally, the PWR OK, BRKR ON, and INPUT OK LEDs light green steadily.
NOTE: If more than one power supply is being installed, turn on all power supplies at the
same time.
"DC Power Supply
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