Why Are Circuit Breakers Important in Aircraft Electrical Systems

The electrical systems of aircraft are often highly complex, tasked with powering everything from cockpit instruments and environmental control units to in-flight entertainment systems and cabin lighting fixtures. Given their diverse uses that are often essential for aircraft operation, these systems must be safeguarded against potential electrical faults that could jeopardize safety or functionality in flight. Among the most vital protective devices in this regard are circuit breakers, devices that play a central role in maintaining operational integrity.

In this blog, we will provide an overview of circuit breakers and the importance they hold in aviation, covering common types found across the industry and their general roles for electrical safety.

Why Do Circuit Breakers Do For Aircraft?

Regardless of type, the core use of a circuit breaker is to interrupt the flow of electrical current when abnormal conditions like overloads or short circuits occur, safeguarding downstream elements from potential damage or wear. Unlike fuses that must be replaced after activation, circuit breakers are notable for generally offering resetability, allowing systems to resume normal operations with ease once the fault condition has cleared or been addressed.

The Main Roles of Circuit Breakers in Aircraft

System Protection: These devices prevent electrical faults from damaging sensitive components by cutting off flow.
Fire Hazard Reduction: Limiting the risk of faults overheating wires or equipment dramatically reduces the hazard of fires occurring in an aircraft.
Operational Reliability: Having circuit breakers on board will ensure the continuity of flight-critical systems when unexpected issues occur by isolating faults.
Safety for Maintenance: Circuit breakers offer a clear means for disconnecting circuits during servicing for optimal safety.

As safety is one of the highest concerns of aviation engineering and operations, circuit breakers perform the highly important role of upholding electrical assembly health.

Common Types of Aircraft Circuit Breakers

Different types of circuit breakers are utilized across aircraft to meet the unique needs of varied systems. Each type is thus engineered with specific applications and performance criteria in mind, the following being the most important for one to be familiar with.

Thermal Circuit Breakers

Thermal circuit breakers are among the most common options in the aviation industry, operating by using a bimetallic strip that bends and trips the breaker when heated by excess current. With their simplicity, reliable operation, and ability to be reset once cooled, thermal breakers are popular for protecting lower-current circuits that involve lighting, instrumentation, cabin systems, and similar electronics.

Magnetic Circuit Breakers

Magnetic breakers use the principle of electromagnetic force to trip a circuit when current exceeds a set threshold, allowing them to achieve fast-acting protection against sudden overloads or short circuits. Oftentimes, these circuit breakers are implemented in systems where the ability to carry out rapid fault interruption is essential, such as avionics and communication equipment.

Thermal-Magnetic Circuit Breakers

These hybrid devices combine thermal and magnetic mechanisms, allowing them to protect electronics against long-term overloads and instantaneous surges alike. This dual-protection capability makes them widely adaptable for mixed-load applications, with their use being common in circuits that power sensitive electronic systems.

Remote-Controlled Circuit Breakers (RCCBs)

RCCBs are becoming increasingly common in more advanced aircraft, these devices providing the ability to be monitored and operated electronically from a cockpit. Coupled with ease-of-integration within digital monitoring systems, these circuit breakers are typically employed in modern airliners and advanced business jets for electrical power distribution management.

How Circuit Breakers Protect Critical Aircraft Systems

The protection offered by circuit breakers extends across virtually every aircraft subsystem that utilizes power, their role being essential for upholding safe, uninterrupted operations.

Major Areas of Protection

Avionics Systems: Circuit breakers safeguard navigation, communication, and monitoring systems from electrical anomalies, preserving pilot situational awareness.
Flight Control Systems: While many modern aircraft take advantage of redundancy, circuit breakers ensure electrical faults do not compromise actuator or control surface reliability to deter reliance on backups.
Cabin Systems: Breakers can safeguard lighting, galley, and entertainment circuits to prevent passenger discomfort or service interruptions during flight.
Power Distribution Networks: Circuit breakers tend to only isolate faults in the affected part of an aircraft’s power network, preventing cascading failures that could negatively impact critical systems.

The Importance of Proper Design and Maintenance

To ensure that any circuit breaker installed in an aircraft is able to best perform its expected role and exhibit a long, reliable service life, it is important to secure quality-assured options for any assembly or maintenance need.

Important Considerations When Purchasing Breakers

Rated Capacity: Any breaker one intends to purchase should be carefully matched to the load capacity of the system it will protect.
Routine Testing: Aircraft should undergo scheduled inspections and checks, with breakers being regularly tested for response accuracy.
Replacement Cycles: Aging circuit breakers should be replaced preemptively to prevent in-flight malfunctions, with manufacturer guidelines often providing information on average intervals.
Crew Training: Pilots and crew should be trained to identify tripped breakers and follow established procedures for resetting them.

Securing Reliable Circuit Breakers for Aviation

Here at ASAP Purchasing, we are proud to connect our customers with a diverse selection of aviation parts, our wide range of quality-assured circuit breaker solutions being ready for purchase with the benefit of competitive pricing and timely fulfillment. We encourage you to explore our website at your leisure to locate items of interest, our curated catalogs and search tools making the process simple.

Once you are ready to make a purchase, you can always fill out and submit a Request for Quote (RFQ) form through our website with information on your needs. We will always respond to these as quickly as possible, utilizing provided details to formulate and present the most competitive options. With team members on standby to support you through fulfillment, be sure to choose ASAP Purchasing today!