737 MAX Flight Crew Operations Manual
Electrical -
System Description
6.20.2
MN-FLT-OH-201
Ground Service
For ground servicing, a ground service switch is on the forward attendant’s panel.
The switch provides ground power directly to the AC ground service buses for
utility outlets, cabin lighting and the battery charger without powering all airplane
electrical buses. The ground service switch is a momentary push button and is
overridden when both AC transfer buses are powered.
Electrical Power Schematic
EXTERNAL AC
RECEPTACLE
HOT BAT BUS
SWITCHED
HOT BATTERY BUS
DC BUS 2
DC BUS 1
DRIVE
GEN
1
GEN
DRIVE
GEN
2
GEN
GEN APU
TR2
TR3
TR1
GND SERVICE
GND SERVICE
RELAY
RELAY
AIRPLANE CONFIGURATION - IN FLIGHT
ENGINE GENERATOR CONNECTED TO RELATED BUS
BUS TRANSFER SWITCH - AUTO
BATTERY SWITCH - ON
STANDBY POWER SWITCH - AUTO
INV
TO APU STARTER
CHGR
BATT
CROSS BUS
TIE RELAY
115V AC GND
SERVICE BUS 2
115V AC
MAIN BUS 2
BUS A & B
GALLEY
BUS C & D
GALLEY
115V AC
MAIN BUS 1
115V AC GND
SERVICE BUS 1
AC TRANSFER BUS 2
AC TRANSFER BUS 1
BATTERY BUS
DC STANDBY BUS
AC STANDBY BUS
CHGR
BATT
AUX
BAT
AUX BAT
GCB1
GCB2
BTB1
BTB2
March 1, 2021