GE Industrial Solutions BDCBB H569-445 - Manual (Page 29)

Secondary DC Power Distribution Bay H569-445
Issue 3 June 2012 29
Discharge Return Bus Options
Discharge return bus options for terminating fuse or circuit breaker return leads may
either be internally mounted in the cabinet or externally mounted outside the
distribution bay on a cable rack.
Internal
The internal discharge return bus bar option terminates return cables from the battery
plant at the top (or bottom) of the cabinet as shown in Figure 12. There is a left-side bus
that interconnects to return bars mounted on the three left mounted fuse or circuit
breaker panels and a right-side bus for the right mounted panels. The bus at the top of
the cabinet is designed for terminating six 3/8 inch double-hole terminal lugs on 1 inch
centers with a tongue width up to 1.7 inches wide. Each panel mounted discharge
return bus is designed for terminating up to 2 gage cable with 1/4 inch double-hole
terminal lugs on 5/8 inch centers.
The advantage of internal returns is that load leads are paired at the fuse or circuit
breaker and eliminates the need for identification tags on each return lead. The
drawback to this cabling scheme is that you are limited to 1200 amps per side so for
multi-load BDFB’s requiring from 1200A-2400A capacity per side requires that input
returns must be located at the top and bottom of the cabinet with returns from the
battery plant split between the top and bottom bus bars. A second concern is the
potential cable congestion resulting from twice the number of leads in the distribution
bay. For these reasons, the internal discharge return option is recommended only for
applications with smaller ultimate capacities. For most applications, the external return
bus option is recommended.
External
The external discharge return bus bar options are shown in Figure 19 and Figure 20. The
external bus is mounted on a standard 15 or 20 inch ladder type cable rack. ED83019-50
Group 13 (150021156) and Group 13A (150021157) are rated for 2400 amperes of
current. Option 150021156 provides the first bus bar and the cable rack mounting
hardware. Option 150021157 provides a bus bar, the connecting bus bar and insulating
standoffs for stacking additional tiers as required. Refer to ED83019-50 drawing for
other ground bar options.