Install a DC Power Supply

To install a DC power supply, follow this procedure:

1. Verify that the power from the DC power source is shut off. Ensure that the voltage across the leads of the DC power cables that you are connecting is 0 V and that there is no chance that the cable leads might become active during connection.
2. Verify that the power switch on the power supply faceplate is in the OFF (O) position.
3. Attach an ESD strap to your bare wrist and connect the strap to one of the ESD points on the chassis.
4. Grasp the handle on the power supply faceplate with one hand and place the other hand under the unit to support it.
5. With a finger of the hand that is grasping the handle, lift and hold up the safety interlock lever, which is just below the power switch.
6. While holding the safety interlock lever up, slide the power supply into the chassis until it contacts the backplane.
7. Still holding the safety interlock lever up, turn the extractor/inserter clockwise until the power supply engages with the connectors on the backplane. See Figure 59.
8. Push the safety interlock lever down.
9. Using a Phillips screwdriver, tighten (but do not overtighten) the thumbscrew at each upper corner of the power supply faceplate.

Figure 59: Install a DC Power Supply

10. Slide the grounding cable lug onto the grounding studs at the lower right corner of the power supply faceplate. Secure the lug, first with locking washers, then with nuts. Using a 7/16-in. nut driver or wrench, tighten the nuts.  
    
    

    Do not substitute a metric nut driver or wrench. A tool that does not fit the nuts exactly can damage them. If a 7/16-in. tool is not available, use pliers or an adjustable wrench.

    
    
11. If the protective shield is installed over the power supply terminals, use a Phillips screwdriver to loosen and remove the screws that secure the shield to the power supply (see Figure 60).

Figure 60: Remove the Protective Shield from the Terminal Studs

12. Slide the power cable lugs onto the terminal studs on the power supply faceplate (see Figure 61):

• Connect the positive (+) source cable lug to the return terminal, which is labeled RTN.
• Connect the negative (-) source cable lug to the input terminal, which is labeled -48V.

Run the power cables to the left on the left power supply, and to the right on the right power supply. This arrangement enables you to replace a power supply without having to detach the cables from the other power supply. 

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 circuit breaker box. You must ensure that the connections at the circuit breaker box maintain the proper polarity. The power source DC cables might be labeled (+) and (-) to indicate their polarity.

Figure 61: Attach Cables to a DC Power Supply

13. Secure the cable lug to the terminal studs, first with locking washers, then nuts. Using a 7/16-in. nut driver or wrench, tighten the nuts.  
    
    

    Do not substitute a metric nut driver or wrench. A tool that does not fit the nuts exactly can damage them. If a 7/16-in. tool is not available, use pliers or an adjustable wrench.

    
    
14. Verify that the power cabling from the source DC breaker to the power supply is correct.
15. Reinstall the protective shield covering the terminal studs.
16. Press the power switch on the power supply to the ON ( | ) position. Verify that the green LED labeled OK on the power supply faceplate eventually lights steadily.  
    
    

    After a power supply is turned on, it can take up to 60 seconds for status indicators—such as LEDs on the power supply, show chassis commands, and messages on the craft interface LCD—to indicate that the power supply is functioning normally. Ignore error indicators that appear during the first 60 seconds. If the router is completely powered down 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 down the router again, first issue the CLI request system halt command. For complete instructions, see Disconnect DC Power from the Router. If after powering on the power supply you must power it off, wait at least 60 seconds. After powering off a power supply, wait 60 seconds before turning it back on.