Figure 10-1 Dc Power - Cisco BPX-BXM-155-8DX Installation And Configuration Manual

DC Power Input Connections
Step 4 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 (90 lug if using conduit box) to terminate the wires.
Ensure that the polarity of the DC input wiring is correct! Connections with reversed
Caution
polarity may damage the equipment.
Remember that this is a positive ground system.
Warning
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.

Figure 10-1 DC Power

Battery
power
Safety
ground
Earth ground
DC ground
Terminate the DC input wiring to a DC source capable of supplying at least 50 amperes. A 50A DC
Step 5
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/conduit to a solid
office (earth) ground.
Note
Step 6 If the system is equipped with dual power feed, repeat steps 1 through 6 for the second power feed.
Either replace the cover on the conduit terminating box(es) or attach the plastic cover plate(s) to the
Step 7
terminal block with screws into the two terminal block standoffs. (See Figure 10-2 and Figure 10-3.)
Cisco BPX 8600 Series Installation and Configuration
10-2
-48V
-48V
RTN
PEM
RTN
PEM - Power Entry Module
RTN - Return
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.
Conductive edge
-48V
Backplane
RTN
Circuit card
Legend
Release 9.3.0, Part Number 78-10674-01 Rev. D0, July 2001
Chapter 10 Installing the DC Shelf
DC-DC
converter