Switchgear Layout And Sizing - GE AKD-10 Application Manual

Switchgear layout and sizing

Rules and examples
Switchgear layout considerations
1. Sections can be bussed together if there are matching bus levels
in the adjacent sections. Refer to the sample AKD-10 line-up below.
2. Any breaker compartment shown on the section drawings can be
made blank to provide additional space for mounting protection,
instrumentation, and control devices.
3. Any blank compartment greater than 7 inches high can be used
for instrumentation (except vent compartments).
4. The ampere ratings shown beside each breaker symbol indicate
the range of frame sizes that are allowed in the particular section
arrangement. This takes into consideration the temperature rise
in the section due to breaker loading. Refer to ANSI C37.20.1-1993
para 7.4.2.3 for cumulative circuit breaker loading guidelines.
5. Devices cannot be mounted on breaker cubicle doors. Refer to
the instrument panel drawings on page 44 for breaker control
device mounting.
6. 3200A, 4000A, and 5000A fuse roll-outs are the same size as
their respective breakers, therefore any compartment shown
with a 3200, 4000 or 5000 amp breaker will also accommodate
a fuse roll-out and vice versa.
7. Front busway connections to a circuit breaker require a blank
compartment above the breaker for busway above or a blank
compartment below the breaker for busway below.
8. Use of fused breakers does not necessarily require 200kA bus
LEGEND & NOTES
MID BUS LEVEL IS NOT AVAILABLE AT 5000A
*
(USE ONLY UPPER OR LOWER BUS LEVELS)
SAMPLE AKD-10 LINE-UP
TO
TRANS-
FORMER
MAIN
TRANSFORMER
TRANSITION
22"
TT22-1 MT22-1
TRANSFORMER BUS CONN
TRANSITION MAIN OR TIE
800A
21" 21"
2000A 800A
21" 21"
800A 800A
21" 21"
800A 800A
21" 21"
22" 22"
F22-1
BUS CONN
FEEDER
bracing. Bus bracing should be based on the available short
circuit current on the switchgear bus.
9. 200kA bus bracing can limit feeder breaker placement. 200kA
bus bracing does not allow adjacent 22 inch wide sections.
10. Factory review of layout is required for bus bracing greater
than 100kA
11. Some cable entrance designs are not suitable for service
entrance. Consult the factory if service entrance is required for
the incoming cable section.
12. Additional cable and conduit space is available by making
breaker sections wider (22 inch wide to 30 inch wide or 30 inch
wide to 38 inch wide) or by making the line-up deeper (7 or 14
inches). Refer to table 32.1 for switchgear depth options.
13. Maximum shipping section widths are 120 inches for indoor
construction and 96 inches for outdoor construction.
Special considerations for 5000 amp equipment
1. 5000 amp equipment is available in indoor or outdoor walk-in
aisle construction only. 5000 amp breakers are not available in
outdoor NEMA 3R non-walk-in construction.
2. Minimum depth of a 5000A breaker section is 74 inches.
3. Upper and lower bus levels are available at 5000 amps. The
center bus level is not available at 5000 amps.
4. 5000 amp bus is available as a bare bus design or with bus
compartment barriers. Insulated/isolated bus design is not
available on 5000 amp equipment.
5. Sections adjacent to a 5000 amp transformer transition section
must be 38 inches wide, minimum.
OUTGOING
INCOMING
CABLE CONNECTION (OTHER THAN FEEDER BREAKER)
FEEDER BUSWAY
REAR POSITION
FEEDER BUSWAY
FRONT POSITION
BUSWAYS
800A
ABOVE=FRONT POS'N
B/W
21"
2000A
800A
TIE
21"
800A
800A
B/W
21"
BUSWAYS
800A
ABOVE=REAR POS'N
21"
22" 22"
MT22-8 F22-12
BUS CONN BUSWAY CONN
TIE FEEDER
B/W
BUSWAY CONNECTION
FEEDER CABLE CONNECTION
INCOMING BUSWAY
FRONT POSITION
BUS LEVEL
BUSWAYS
ABOVE=FRONT POS'N
B/W
21" 21"
2000A
MAIN
MID
BUS
21" 21"
800A
BUS
21" 21"
800A
21"
21"
SECTION WIDTH
22"
SECTION CODE
MT22-7
BUSWAY CONN
DESCRIPTION
MAIN OR TIE
UPPER
BUS
*
LOWER
SECTION
33