Related
Documentation
Installing an M120 AC Power Supply on page 242•
• Electrical Specifications for the M120 AC Power Supply on page 95
• M120 AC Power Supply Description on page 72
• M120 Power Supply LEDs on page 73
Connecting Power to a DC-Powered M120 Router
You connect DC power to the router by attaching power cables from the DC power sources
to the terminal studs on the power supply faceplates. To connect power to the router,
you must provide power cables (cable lugs are supplied with the router). For power cable
specifications, see “M120 DC Power, Connection, and Cable Specifications” on page 97.
To connect the DC source power cables to the router:
1. Ensure that the voltage across the DC power source cable leads is 0 V and that there
is no chance that the cable leads might become active during installation.
2. Secure the power cable lugs to the terminal studs, first with the flat washer, then with
the nut (see Figure 59 on page 170). Apply between 12 lb-in. (1.4 Nm) and 15 lb-in.
(1.7 Nm) of torque to each nut.
a. Attach the positive (+) DC source power cable lug to the RETURN (return) terminal.
b. Attach the negative (–) DC source power cable lug to the –48V (input) terminal.
3. Loosen the captive screw on the cable restraint on the lower edge of the power supply
faceplate.
4. Connect each DC power cable to the appropriate external DC power source.
NOTE: For information about connecting to external DC power sources,
see “M120 DC Power, Connection, and Cable Specifications” on page 97.
169Copyright © 2018, Juniper Networks, Inc.
Chapter 21: Providing Power to the M120