Figure 75: Typical Dc Source Cabling To The Router - Juniper MX2020 Hardware Manual

MX2020 3D Universal Edge Router Hardware Guide
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178
If feeds that connect to one PDM fail in a redundant configuration, the other feed kicks
in to provide full power .
Figure 75 on page 178 shows a typical DC source cabling arrangement.

Figure 75: Typical DC Source Cabling to the Router

DC power supply on MX2020
Chassis grounding points
(central office ground)
All DC PSMs in a subsystem share the load (the nine PSMs on the top half share the load,
as well as the nine PSMs on the bottom share the load). If one PSM fails in a redundant
configuration, the remaining PSMs provide power to FRUs. Up to eighteen PSMs may be
required to supply power to a fully configured router. Nine PSMs in the lower card cage
supply power to the two CB-REs (active and redundant), eight SFBs, lower ten MPCs,
two lower fan trays and one fan tray on the top half. Nine PSMs in the upper card cage
supply power to the two upper fan trays, upper ten MPCs, two CB-REs (active and
redundant), eight SFBs, and a fan tray in the lower card cage. A portion of power from
each zone is reserved to power critical FRUs. These FRUs allow the system to operate
even if power to a complete zone fails.
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 PDM.
WARNING: For field-wiring connections, use copper conductors only.
CAUTION: Power cords and cables must not block access to device
components or drape where people could trip on them.
MX2020 DC Power Distribution Module Description on page 94
Central office
secondary DC
power distribution
Ground
window
Batteries
Power plant and batteries
Central
in same building
office ground
(+)
Copyright © 2015, Juniper Networks, Inc.
Rectifiers AC
Plant
controls
and to indicate
(-)