Juniper MX2020 Hardware Manual page 315

Copyright © 2013, Juniper Networks, Inc.
WARNING: Before performing AC power procedures, ensure that power is
removed from the AC circuit. To ensure that all power is off, locate the circuit
breaker on the panel board that services the AC circuit, switch the circuit
breaker to the off position, and tape the switch handle of the circuit breaker
in the off position.
WARNING: Do not touch the power connectors on the PDM . They can contain
dangerous voltages.
CAUTION: To maintain proper cooling and prevent thermal shutdown of the
operating power supply unit, each PDM slot must contain either a PDM or a
blank panel. If you remove a PDM, you must install a replacement PDM or a
blank panel shortly after the removal.
NOTE: After powering off a PDM, wait at least 60 seconds before turning
the circuit breaker back on.
To remove a three-phase wye AC PDM:
Switch off the dedicated customer site circuit breakers to the PDM being remove.
1.
Make sure that the voltage across the AC power source cord is 0 V and that there is
no chance that the cord might become active during the removal process.
Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect
2.
the strap to one of the ESD points on the chassis.
Switch off ( ) the AC PSMs that are powered only from the AC PDMs being removed.
O
3.
NOTE: After powering off a PDM, wait at least 60 seconds before turning
it back on.
Remove the ESD grounding strap from the ESD point on the chassis, and attach it to
4.
an approved site ESD grounding point. See instructions for your site.
Disconnect the AC power cord (see
5.
Chapter 13: Replacing MX2020 Router Hardware Components
Figure 132 on page 290) from the power source.
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