Specifications

7-74 Information Manual
Section 7 Cirrus Design
Airplane Description SR20
Circuit Breakers and Fuses
Individual electrical circuits connected to the Main, Essential, and
Non-Essential Buses in the airplane are protected by re-settable circuit
breakers mounted in the circuit breaker panel on the left side of the
center console.
Essential Buses
The circuit breaker panel Essential Bus is powered by ALT 2 from the
MCU Essential Distribution Bus through the 25-amp ESSENTIAL
POWER circuit breaker and from BAT 2 through the 30-amp BATTERY
2 circuit breaker. The Essential Bus is also powered by ALT 1 and BAT-
1 through an isolation diode connecting the Main and Essential
Distribution Buses in the MCU. The autopilot and Essential avionics
equipment are powered directly from the Essential Distribution Bus in
the MCU through a 25-amp circuit breaker on the Distribution Bus.
Power from the 15-amp AVIONICS circuit breaker is also controlled
through the AVIONICS master switch on the bolster switch panel.
Main Buses
The circuit breaker panel Main Bus 1 and Main Bus 2 are powered by
ALT 1 and BAT 1 from the MCU Main Distribution Bus through 25-amp
circuit breakers on the Distribution Bus. ALT 2 and BAT 2 are
prevented from powering the Main Buses by the isolation diode
interconnecting the MCU distribution buses. Loads on circuit breaker
panel Main Buses are shed by pulling the individual circuit breakers.
The 15-amp AVIONICS circuit breaker on Main Bus 1 powers all loads
on the Non-Essential Avionics Bus. Power from the 15-amp AVIONICS
circuit breaker is also controlled through the AVIONICS master switch
on the bolster switch panel.
Non-Essential Buses
The circuit breaker panel contains two Non-Essential Buses, the Non-
Essential Equipment Bus and the Avionics Non-Essential Bus. The
Avionics Non-Essential Bus is powered through the 15-amp
AVIONICS circuit breaker on Main Bus 1 and is discussed above. The
Non-Essential Equipment Bus is powered by ALT 1 and BAT 1 from
the MCU Main Distribution Bus through a 25-amp circuit breaker. ALT
2 and BAT 2 are prevented from powering the Non-Essential
Equipment Bus by the isolation diode interconnecting the MCU
March 2010