Table Of Contents
Installing the DC Shelf
Preparing for DC Power Installation
DC Power Input Connections
Card Slot Fuses
Fan Power Fuses
Installing the DC Shelf
This chapter explains how to connect the DC power supply to the BPX switch.
Contents of this chapter include:
•
DC Power Input Connections
• Card Slot Fuses
• Fan Power Fuses
Before proceeding in this chapter, complete the following procedures:
• "Installation with Cisco Cabinets including 7000 Series Routers"
• "Installation in Customer Cabinet"
Preparing for DC Power Installation
Before you begin, you should do the following:
•Verify that you have all necessary DC power cables.
•Verify that you have all cabinet earthing cabling and ground points.
•Dedicated grounds are installed to the switch.
(Suitable crimps can be obtained from RS Components at http://rswww.com with product codes of 531-021 for a 10mm 2 cable and 119-160 for a 6mm 2 cable.)
•Confirm that power is from isolated supplies.
•Verify that -48 VDC, 50 amp dual feeds are connected to the switch from the power distribution unit.
•Inspect all power and ground connections. Check for voltage and polarity.
DC Power Input Connections
The following are the two ways to configure a DC-powered BPX switch:
•Single DC Power Entry Module, single power feed
•Dual DC Power Entry Module, dual power feed
Figure 10-1 illustrates a wiring connection from a -48 VDC power source to one or two DC Power Entry Modules. The wiring is provided by the installer.
Figure 10-1 DC Power
Figure 10-2 shows a metallic conduit box that meets all electrical codes for attaching electrical conduit is factory-installed.
Figure 10-2 DC Power Connections—With Conduit Box
Figure 10-3 illustrates a simple plastic cover that is also enclosed for customers who do not require conduit protection for the input power leads. If required by local electrical code, use conduit.
Figure 10-3 DC Power Connections—Without Conduit Box
Only a source that complies with the safety extra low voltage (SELV) requirements in UL1950, CSA C22.2 No. 950, EN60950 may be connected to a BPX switch DC system.
To make DC power connections to the BPX switch, use the following procedure:
Step 1 Locate the conduit terminating box, one for each Power Entry Module (see Figure 10-2).
Step 2 Remove the two cover screws and lift off the cover. If conduit is required, go to Step 3. If conduit is not required, go to Step 4.
Step 3 Determine which knockout to remove (rear or bottom). Remove knockout and install conduit fitting.
Step 4 If conduit is not required, remove the conduit box by removing the two screws, one above the terminal block and one below it.
Step 5 Run three wires from the DC terminal block to a source of 48 VDC.
Use 8 AWG wire (or metric equivalent for E1 systems).
Use a #10 screw ring lug designed for 8 AWG wire (90Ч lug if using conduit box) to terminate the wires.
Caution Ensure that the polarity of the DC input wiring is correct! Connections with reversed polarity may damage the equipment.
Warning Remember that this is a positive ground system. Connect the positive lead to the +RTN terminal. Connect the negative lead to the -48V terminal. Connect the earth ground to the middle terminal labeled SAFETY GROUND (see Figure 10-1, Figure 10-2, and Figure 10-3). For personnel safety, the green/yellow wire must be connected to safety (earth) ground at both the equipment and at the supply side of the DC wiring.
Step 6 Terminate the DC input wiring to a DC source capable of supplying at least 50 amperes. A 50A DC circuit breaker is required at the 48 VDC facility power source. An easily accessible disconnect device should be incorporated into the facility wiring. Be sure to connect the ground wire or conduit to a solid office (earth) ground.
Note Primary overcurrent protection is provided by the building circuit breaker. In North America, this breaker should protect against excess currents, short circuits, and earth faults in accordance with NEC ANSI NFPA 70/CEC.
Step 7 If the system is equipped with dual power feed, repeat steps 1 through 6 for the second power feed.
Step 8 Either replace the cover on the conduit terminating box(es) or attach the plastic cover plate(s) to the terminal block with screws into the two terminal block standoffs (see Figure 10-2 and Figure 10-3).
Step 9 Proceed to Chapter 13, "Installing the BPX Switch Cards."
Card Slot Fuses
Fuses for each card slot are installed to the backplane of the BPX switch to protect against catastrophic backplane damage in the event of a shorted connector power pin. Backplane fuses should rarely, if ever, need replacement. The card slot fuses are designated F4 through F18, corresponding to card slot numbers 1 through 15, respectively.
For instructions on replacement of these fuses, see "Replacing Parts." Contact Cisco Customer Service for assistance regarding their replacement.
Caution For continued protection against risk of fire, replace only with the same type and rating of fuse. Fuses should be replaced only after all power to the BPX switch has been turned off.
Fan Power Fuses
Fan fuses are located on the backplane of the BPX switch to protect against catastrophic backplane damage in the event of a shorted fan cable. Backplane fuses should rarely, if ever, need replacement. The fuses are designated F1 through F3, corresponding to fans 1 through 3.
Caution For instructions on replacement of these fuses, see
"Replacing Parts." Contact Cisco Customer Service for assistance regarding their replacement.
Warning For continued protection against risk of fire, replace only with the same type and rating of fuse. Replace fuses only after all power to the BPX switch has been turned off.
