Replacing an M10i DC Power Cable

A DC-powered router has up to four load-sharing DC power supplies. The router must have at least two DC power supplies, and any two DC power supplies can provide full power to the router. The power cords on a redundant power supply are hot-removable and hot-insertable, as described in M10i Field-Replaceable Units (FRUs). For M10i routers with only two DC power supplies, you must power off the router before replacing the DC power cables. See Powering Off an M10i Router .

1. Removing a DC Power Cable
2. Installing a DC Power Cable

Removing a DC Power Cable

To remove a DC power cable:

1. For each power supply, press the power switch on the power supply faceplate to the OFF (O) position.

   Note: If you are power cycling the power supply rather than shutting it off for a time, wait at least 60 seconds after turning it off before turning it back on. If you need to power it off again, wait for at least 60 seconds after powering it on.

2. Shut off the power flowing from both external power sources, so that the voltage across the leads of the DC power cables is 0 V. Ensure that there is no chance that the cable leads might become active during the procedure.
3. Using a number 1 Phillips screwdriver, turn the screw on each field-wiring terminal counter-clockwise to loosen the terminal connector from around the cable lug.
4. Remove the cables from the terminal connectors and from the hook located on the faceplate to the right of the field-wiring terminals.
5. Verify that the removed cables are not touching or blocking access to any router components.

Installing a DC Power Cable

Connect DC power to the router by inserting DC power cables into the field-wiring terminals on the faceplate of each power supply. For information about the required cable type, see M10i DC Power Cable and Lug Specifications.

1. Verify that there is no power flowing 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 a licensed electrician has attached a listed DC power cable lug to the DC power cable.
3. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
4. Verify that the power switch on the power supply faceplate is in the OFF (O) position.
5. Loop the DC power cables through the hook located on the faceplate to the right of the field-wiring terminals.
6. Depending on the type of DC power cable lugs used, loosen or remove the screws on the field-wiring terminals.
7. Insert the DC 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 DC power cable lug. Apply between 8 lb-in. (.9 Nm) and 9 lb-in. (1.02 Nm) of torque to each screw.
   1. Insert the positive (+) source cable into the return terminal, which is labeled RTN.
   2. Insert the negative (–) source cable into the input terminal, which is labeled –48V.

   Caution: You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate 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 DC power cables that attach to the terminal studs on the power supply faceplate.

   Note: The DC power supplies in slots P/S 0 and P/S 1 must be powered by dedicated power feeds derived from feed A, and the DC power supplies in slots P/S 2 and P/S 3 must be powered by dedicated power feeds derived from feed B. This configuration provides the commonly deployed A/B feed redundancy for the system.

8. Verify that the DC source power cabling is correct, that the DC cables are not touching or blocking access to router components, and that they do not drape where people could trip on them.

Figure 1: Connecting DC Power Cables