Embraer EMB145 Operation Manual page 1711

ELECTRICAL
GROUND SERVICE BUS
The Ground Service Bus is energized by connecting the GPU
connector to the airplane receptacle, provided the batteries and
generators are not connected to the buses (GPC, BC 1 and BC 2 are
open).
The Ground Service Bus supplies electrical power for airplane
servicing and maintenance while on the ground. It functions
independently of the Electrical Distribution Logic and does not
energize all electrical distribution buses.
The following lights will be powered by the Ground Service Bus:
Passenger cabin lights;
Lavatory lights;
Galley lights;
Courtesy/stairs lights;
Cockpit dome lights;
Baggage/service compartment lights.
Page
2-05-05 10
AIRPLANE
OPERATIONS
MANUAL
GROUND SERVICE SCHEMATIC
Code
01 REVISION 36