A – c/b`s

B737Theory
BOEING 737NG
Foreword.
This Electrical Supplement is an addition to the B737Theory Systems Manual and is restricted in use,
it is not allowed to copy and distribute the manual without notification to the B737Theory custodian.
This Supplement is designed as an ELECTRICAL POWER SOURCE,– and CIRCUIT BREAKER LOCATION
directory and it must be understood that there are differences amongst various NG model aircraft.
About
The B737Theory Facebook page, Manual and Supplement are solely created to interact throughout
the B737NG community and has no direct link to any Company.
THE CONTENT SHALL NOT BE USED FOR ACTUAL OPERATION OF THE AIRCRAFT
B737Theory
The goal of the Facebook page, Manual and Supplement is to expand Boeing 737NG theoretical
knowledge by increasing the amount of visitors aiming for interaction. Recommend the page through
your private Facebook page rather than sharing the posts (too bad I can’t remove the share option in
FB) as I’ve put in a lot of time, research and knowledge in the posts and manuals.
I have re-designed this part of the Manual as an Electrical Sources Supplement using alphabetical
order on subjects. I expanded the Electrical Panels, Busses and Circuit Breaker location layouts, which
again may differ on various NG models (600 – 900) but is valuable as a gauge on this subject.
About the author:
I am a retired Instructor Flight Engineer and currently a B737NG Ground School Instructor. I enjoy
expanding knowledge on aircraft systems and publishing this, making it available to users around the
World. I combine courseware development skills with theoretical aviation knowledge to explain
several systems written in my own way, sometimes a little further than needed but creating a more
“complete picture” to the basic standard required systems knowledge.
Corrections and/or recommendations are welcome and can be send to bertdaantje@gmail.com, or
send a “message” on https://www.facebook.com/B737Theory/ and I’ll look into it, when confirmed
I’ll update the document.
Thank you and enjoy . . .
ELECTRICAL SUPPLEMENT
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B737Theory
BOEING 737NG
Contents
Foreword. ................................................................................................................................................ 3
Electrical schematic ................................................................................................................................. 7
AC ELECTRICAL BUSSES............................................................................................................................ 8
115 VAC Transfer Bus 1 .................................................................................................... 8
115 VAC Transfer Bus 1 - Sect 1 ....................................................................................... 9
115 VAC Transfer Bus 1 - Sect 2 ....................................................................................... 9
28 VAC Transfer Bus 1 .....................................................................................................10
115 VAC Transfer Bus 2 ...................................................................................................10
115 VAC Transfer Bus 2 - Sect 1 ......................................................................................11
115 VAC Transfer Bus 2 - Sect 2 ......................................................................................11
28 VAC Transfer Bus 2 .....................................................................................................12
115 VAC Main Bus 1.........................................................................................................12
115 VAC Main Bus 2.........................................................................................................13
115 VAC Standby Bus ......................................................................................................13
28 VAC Standby Bus ........................................................................................................14
115 VAC Ground Service Bus 1 ........................................................................................14
28 VAC Ground Service Bus 1..........................................................................................15
115 VAC Ground Service Bus 2 ........................................................................................15
28 VAC Ground Service Bus 2..........................................................................................15
DC ELECTRICAL BUSSES ......................................................................................................................... 16
28 VDC – Hot Battery Bus ................................................................................................16
28 VDC – Switched Hot Battery Bus .................................................................................16
28 VDC – Battery Bus .......................................................................................................17
28 VDC – Battery Bus - Sect 1..........................................................................................17
28 VDC - Battery Bus - Sect 2 ..........................................................................................17
28 VDC - Battery Bus - Sect 3 ..........................................................................................18
28 VDC Bus 1 ...................................................................................................................19
28 VDC Bus 1 - Sect 1 ......................................................................................................20
28 VDC Bus 1 - Sect 2 ......................................................................................................20
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BOEING 737NG
28 VDC Bus 2 ...................................................................................................................21
28 VDC Bus 2 - Sect 1 ......................................................................................................22
28 VDC Bus 2 - Sect 2 ......................................................................................................22
28 VDC Ground Service Bus ............................................................................................23
28 VDC – Standby Bus - Sect 1 ........................................................................................24
28 VDC - Standby Bus - Sect 2.........................................................................................24
Circuit Breaker (panel) Locations .......................................................................................................... 25
P6 – 1 ...............................................................................................................................26
P6 – 2 ...............................................................................................................................26
P6 – 3 ...............................................................................................................................27
P6 – 4 ...............................................................................................................................27
P6 – 5, Standby Power Control Unit..................................................................................28
P6 – 11 & P6 – 12.............................................................................................................28
P18 – 1 .............................................................................................................................29
P18 – 2 .............................................................................................................................30
P18 – 3 .............................................................................................................................30
A – c/b’s ................................................................................................................................................. 31
B – c/b’s ................................................................................................................................................. 33
C – c/b’s ................................................................................................................................................. 33
D – c/b’s ................................................................................................................................................. 34
E – c/b’s ................................................................................................................................................. 35
F – c/b’s ................................................................................................................................................. 36
G – c/b’s................................................................................................................................................. 37
H – c/b’s ................................................................................................................................................. 37
I – c/b’s .................................................................................................................................................. 38
L – c/b’s ................................................................................................................................................. 38
M – c/b’s ................................................................................................................................................ 40
N – c/b’s................................................................................................................................................. 41
O – c/b’s................................................................................................................................................. 41
P – c/b’s ................................................................................................................................................. 41
R – c/b’s ................................................................................................................................................. 42
S – c/b’s ................................................................................................................................................. 42
ELECTRICAL SUPPLEMENT
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B737Theory
BOEING 737NG
T – c/b’s ................................................................................................................................................. 43
V – c/b’s ................................................................................................................................................. 44
W – c/b’s................................................................................................................................................ 44
Y – c/b’s ................................................................................................................................................. 44
Z – c/b’s ................................................................................................................................................. 45
ELECTRICAL SUPPLEMENT
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B737Theory
BOEING 737NG
AC ELECTRICAL BUSSES
The AC electrical transfer system operates with two basic principles accomplished by operation of
the Bus Power Control Unit (BPCU):
1. There is no paralleling of the AC sources of power possible.
2. The source of power being connected to a transfer bus automatically disconnects an existing
source. (or else there is AC paralleling)
The electrical busses are arranged with the most important AC busses first, where after the lesser
(but still) important busses. After the AC selection you’ll find the DC busses starting with the Battery
busses followed by the Main busses, etc.
Under each bus you’ll find how the respective bus receive Normal power, and when applicable an
Alternate power source.
The powered components are in Alphabetical order except the red bold faced circuit breakers. They
refer to (sub) busses and can thereby be isolated, pulling that respective circuit breaker.
115 VAC Transfer Bus 1
Normal power – IDG 1
Alternate power – XFR bus 2, APU gen or GPU via BTB’s
28 VAC XFR BUS
GALLEY BUS C & D
GROUND SERVICE BUS 1
MAIN BUS 1
XFR BUS 1 SECT 1
XFR BUS 1 SECT 2
APU START CONVERTER
B SYS ELEC HYDR PUMP
BOOST PUMP TANK l FWD
BOOST PUMP TANK 2 AFT
EQUIP COOL SUPPLY FAN ALT
MIDU
TEMP CONT 35 DEG L
TEMP CONTL
TEMP CONT MAN
TRU 1
TRU 3 ALT
VACUUM WASTE BLOWER
ELECTRICAL SUPPLEMENT
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BOEING 737NG
Circuit Breaker (panel) Locations
A generic 3 column list of B737NG circuit breaker locations on their respective circuit breaker panels.
The columns are shown in an Alphabetical order of the powered components, than the panels and
the Alpha/Numerical positions.
Also here, the lay-out can be different amongst several NG type
Boeing 737’s.
P6-1
P6-2
P6-3
P6-5
P6-4
P6-11 & P6-12
NAVIGATION, INSTRUMENTS & COMMUNICATION
SYSTEMS
FUEL SYSTEM, LIGHTING & LANDING GEAR
STANDBY POWER CONTROL UNIT
AIR CONDITION & ELECTRICAL
WINDOW HEAT
P18-1
P18-2
P18-3
NAVIGATION
INSTRUMENTS & COMMUNICATION
ANTI-ICE & LIGHTING
P91 & P92
POWER DISTRIBUTION PANELS (Located in the E & E Compartment)
ELECTRICAL SUPPLEMENT
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B737Theory
BOEING 737NG
P18 – 1
ELECTRICAL SUPPLEMENT
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B737Theory
BOEING 737NG
A – c/b’s
AC Transfer Bus 1, C phase
AC Transfer Bus 2, A phase
AC Transfer Bus 2, B phase
ACARS CMU AC
ACARS CMU DC
ACARS MU AC
ACMS
ADF 1
ADF 2
ADIRU, Left, AC
ADIRU, Left, DC
ADIRU, Left, EXC
ADIRU, Right DC
ADIRU, Right, AC
ADIRU, Right, EXC
AFCS, Sys A, Engage Interlock
AFCS, Sys A, FCC (DC)
AFCS, Sys A, Mach Trim (AC)
AFCS, Sys A, Mach Trim (DC)
AFCS, Sys A, Sensor Exc (AC)
AFCS, Sys A, Warn Light (Bat)
AFCS, Sys B, Engage Interlock
AFCS, Sys B, FCC (DC)
AFCS, Sys B, Mach Trim (AC)
AFCS, Sys B, Mach Trim (DC)
AFCS, Sys B, Sensor Exc (AC)
AFCS, Sys B, Warn Light (Bat)
Air Cond Bleed Air, Press Ind
Air Cond Bleed Air, Valve Isln
Air Cond Bleed Air, Valves Left
Air Cond Bleed Air, Valves Right
Air Cond Bleed Air, XDCR Left
Air Cond Bleed Air, XDCR Right
Air Cond Mix Valve Pos Ind (6-7)
Air Cond Ovbd Exh Valve, Cont
Air Cond Ovbd Exh Vlv, Recon Cont
Air Cond Overheat (6-7)
Air Cond Pack Cont Valve, Left
Air Cond Pack Cont Valve, Right
Air Cond Pack Cont, Lt Elect AC (8)
Air Cond Pack Cont, Lt Elect DC (8)
Air Cond Pack Cont, Rt Elect AC (8)
Air Cond Pack Cont, Rt Elect DC (8)
Air Cond Pack/Eng Bleed Air, Oht, Lt
Air Cond Pack/Eng Bleed Air, Oht, Rt
Air Cond Ram Air Mod Cont, Left
Air Cond Ram Air Mod Cont, Right
ELECTRICAL SUPPLEMENT
P6-4
P6-4
P6-4
P6-1
P6-1
P6-1
P6-1
P18-1
P6-1
P18-1
P18-1
P18-2
P6-1
P6-1
P6-1
P18-1
P18-1
P18-1
P18-1
P18-1
P18-1
P6-2
P6-2
P6-2
P6-2
P6-2
P6-2
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
P6-4
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C15
C10
C11
E8
E9
E7
E4
A4
A17
E7
E5
E8
C17
C14
C15
D3
D2
C4
D4
C5
D1
B4
B3
C1
B2
C2
B1
B5
A5
A7
B7
A6
B6
D7
D1
D2
C4
C6
C5
A11
A9
B11
B9
C8
C7
A8
B8
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