See Also DC Power Electrical Safety Warnings for Juniper Networks Devices on page 256•
• M7i DC Power Electrical Safety Guidelines on page 255
• M7i Router DC Power Supply Specifications on page 87
• Installing a DC Power Supply on page 173
Installing a DC Power Supply
To install a DC power supply (see Figure 63 on page 174):
1. Verify that there is no power flowing to the power supply from the external power
source, so that the voltage across the leads of the power cables is 0 V. Ensure that
there is no chance that the cable leads might become active during the procedure.
2. Verify that the power switch for the power supply (located on the power supply
faceplate) is in the OFF (O) position.
3. Verify that the grounding cable is attached to the chassis and properly connected to
an earth ground.
4. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist and connect
the strap to one of the ESD points on the chassis. Verify that the router is attached to
a proper earth ground.
5. Place one hand under the power supply and grasp the handle on the faceplate with
the other hand. Slide the power supply into the chassis until it contacts the midplane.
6. Starting with the bottom screw, tighten (but do not overtighten) the thumbscrews
at each corner of the power supply faceplate.
7. Verify that a licensed electrician has attached a listed power cable lug to each power
source cable.
8. Loop the power cables through the hook located on the faceplate to the right of the
field-wiring terminals.
9. Depending on the type of power cable lugs used, loosen or remove the screws on the
field-wiring terminals.
10. Insert the power cable lugs into the appropriate field-wiring terminals. Using a number
1 Phillips screwdriver, turn the screw on each field-wiring terminal clockwise to secure
the power cable lug. Apply between 8 lb-in. (.9 Nm) and 9 lb-in. (1.02 Nm) of torque
to each screw.
a. Insert the positive (+) source cable into the return terminal, which is labeled RTN.
173Copyright © 2019, Juniper Networks, Inc.
Chapter 25: Replacing Power System Components