Installing a DC Power Supply

To install a DC power supply, follow this procedure (see Figure 70, Figure 71, Figure 72, and Figure 73):

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. 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. For more information about ESD, see Preventing Electrostatic Discharge Damage.
4. Grasp the handle on the power supply faceplate with one hand and place the other hand under the supply to support it.
5. Slide the power supply into the chassis until it contacts the midplane.
6. Press the ejector handle toward the faceplate to seat the power supply firmly in the chassis.
7. Tighten (but do not overtighten) the thumbscrews on the power supply faceplate. Turn both thumbscrews simultaneously and at about the same rate (turning them alternately or at very different rates can cause the power supply to become lodged in the slot, making it difficult to turn the screws).
8. If a protective shield is installed over the terminal studs on the power supply, loosen the screws that secure it to the power supply and remove the shield.
9. If nuts and washers are installed on the power supply terminal studs, use a 7/16-in. nut driver or wrench to loosen the outer nut on each stud. Remove the outer nuts and washers, leaving the inner nut and washer on each stud.

   Caution: Do not substitute a metric nut driver or wrench. A tool that does not fit the nuts exactly can damage them.

10. Slide the power cable lugs onto the terminals on the power supply. Replace the outer washers and nuts (in that order) to secure the power cable lugs to the terminal studs.
    1. Connect the positive (+) source cable lug to the return terminal on the power supply, which is labeled RTN.
    2. Connect the negative (–) source cable lug to the input terminal on the power supply, which is labeled –48V.

    Using a 7/16-in. nut driver or wrench, tighten each nut. Apply between 23 lb-in. (2.6 Nm) and 25 lb-in. (2.8 Nm) of torque to each nut.

11. Verify that the DC source power cabling and the grounding cabling are correct, that they are not touching or blocking access to router components, and that they do not drape where people could trip on them.
12. Replace the protective shield over the terminals and tighten the screws that secure it to the power supply.
13. Turn on the DC power source so that voltage flows to the power supply.
14. Press the switch on the power supply faceplate to the ON ( | ) position. Verify that the green OK LED eventually lights steadily and the amber FAULT LED does not light.

    Note: After powering off a power supply, wait at least 60 seconds before turning it back on. After powering on a power supply, wait at least 60 seconds before turning it off. If the router is completely powered off when you power on the power supply, the Routing Engine boots as the power supply completes its startup sequence. If the Routing Engine finishes booting and you need to power off the router again, first issue the CLI request system halt command. For more information, see Disconnecting AC Power from the Router or Disconnecting DC Power from the Router. After a power supply is powered on, it can take up to 60 seconds for status indicators—such as LEDs on the power supply and show chassis commands—to indicate that the power supply is functioning normally. Ignore error indicators that appear during the first 60 seconds.

    Note: When two power supplies are installed, at least one Routing Engine and one FPC must also be installed for both power supplies to power on. In the absence of this minimum load, only one power supply starts. (The router powers on and operates correctly with one power supply, but without the redundancy benefit of a second power supply.)

Figure 70: Power Switch in the Off Position on a DC Power Supply

Figure 71: Installing a DC Power Supply

Figure 72: Connecting Power Cables to a DC Power Supply

Figure 73: Installing the Protective Shield on a DC Power Supply