Maintenance Practices for Air Circuit Breakers: Ensuring Longevity and Performance

March 19, 2024

Complex industrial and commercial systems demand very precise needs, such as the conditionality of a constant and secure electricity supply. At the core of these electrical systems are air circuit breakers (ACBs), which protect equipment from short-circuits, overloads and earth fault conditions.

Also, like any mechanical devices, ACBs must be regularly cared for to guarantee excellent performance and reliability. Such a preventive approach leads to minimized downtime and extended appliance life. Let's consider the maintenance methods that can be utilized to ensure the optimum performance of air circuit breakers.

Frequency of Maintenance Tasks

ACBs serve as the first defense against electrical failures such as short circuits and overloads. However, failure to maintain these safety components might cause serious consequences.

A faulty ACB poses serious safety risks, increasing the likelihood of electrical fires, equipment damage, and personal harm. Additionally, circuit breaker failure can lead to significant costs, including expensive repairs, downtime, and possible productivity losses.

The frequency of maintenance varies according to the kind of ACB and the operational environment. For example, medium-voltage ACBs typically require annual inspections or maintenance after a certain number of operations or as recommended by the manufacturer.

Specific Maintenance Tasks

Visual inspection

It is an essential maintenance task for all circuit breakers, regardless of type. It examines exterior and interior components for wear, damage, or corrosion signs. Periodic visual inspections are an important part of the early prevention of technical problems, which, in the future might bring about accidents or expensive breakdowns.

Begin by inspecting the circuit breaker's main contacts, which are responsible for making and breaking current. Pay close attention to symptoms of wear, especially if the circuit breaker has been subjected to several short-circuit currents before being inspected.

Worn-out contacts might cause anomalous temperature spikes during the circuit breaker's operation, creating a safety risk. Ensure the contacts are properly aligned and the spring pressures are within the manufacturer's specifications.


Another critical facet of ACB maintenance is the operating mechanism, which consists of the device and chassis mechanisms responsible for controlling the opening and closing of the breaker.  All components of this mechanism—springs, closures, and levers—ought to operate accurately. Ensure also that every fastener and bolt is fastened securely.

Conduct insulation resistance tests to assess the insulation materials' quality and carry out contact resistance tests to measure the resistance of electrical connections. Likewise, performing timing tests is crucial to confirm that the ACB functions within the specific parameters recommended by the air circuit breaker manufacturer to ensure optimal performance and safety.


Cleaning: Dirt will affect ACB effectiveness if left unchecked. Inspect the arc chutes for dust and moisture. The presence of black coloration of the arc chute fins is normal and acceptable as long as they are not damaged.

Avoid using wire brushes or emery cloth as they can leave conductive residue that interferes with the arc chutes' performance. Light sanding is the best solution for eliminating any debris, and a vacuum cleaner will suffice for dust removal.

Re-testing following servicing tasks ensures that the ACB operates appropriately and meets safety regulations.


Obtaining certification is an additional desirable part of ensuring quality. Circuit breaker certification verifies that your breakers are functioning correctly and can protect the facility and its inhabitants from electrical hazards.

Importance of Maintenance Components

● Lubrication facilitates the smooth movement of components, minimizing damage caused by friction and ensuring the best possible performance.

● Proper alignment guarantees precise positioning of the components, minimizing strain and increasing the longevity of the circuit breaker.

● Insulation restricts the flow of electric current between different conductors and protects individuals and equipment.

● Regular inspections for air and oil leaks help prevent performance issues and ensure the system's integrity. Optimal air pressure is essential for the efficient operation of the ACB and to safeguard the system.

● Measuring the Dew Point is crucial for maintaining moisture levels within acceptable limits to prevent corrosion and damage.

● Electrical functional tests ensure the system operates correctly and safeguards against malfunctions and excessive loads.

Remember, before conducting any repair operations, ensure all power is switched off at the circuit breaker. Power should only be restored once the circuit breaker has been reassembled.

Status of parameters after maintenance

After maintenance, verify the parameters to ensure the equipment is operating well.

1. Confirm Input Voltage

2. Check the load to the capacity.

3. Check variables in relation to the default limit.

4. Check for any strange sounds.

Advantages of Conducting Routine Maintenance

1. Safety: The primary purpose of circuit breaker maintenance is to guarantee the safety of people and property by ensuring that they function optimally during electrical breakdowns.

2. Reliability: Circuit breakers guarantee a steady power supply by preventing power cuts instigated by system breakdowns, thus keeping plants and appliances in operation.

3. Compliance: Frequent inspection and maintenance of circuit breakers while following the guidelines offered by the air circuit breaker’s manufacturer makes a system compliant with electrical codes and norms.

4. Lifespan Extension: Regular maintenance involves prompt fixing of any concerns, avoiding expensive replacements, and maintaining uninterrupted performance.

5. Performance Enhancement: Properly maintained circuit breakers operate more efficiently, contributing to a general improvement of the power system.

6. Cost Reduction: Regular maintenance allows you to find and resolve minor problems that would eventually develop into pricey repairs or replacements.

7. Environmental Impact Reduction: Well maintained circuit breakers contribute to better energy efficiency, which minimizes negative impact on the environment by avoiding energy waste and power quality issues.


For optimal maintenance of circuit breakers, create an inspection plan that takes into account switching frequency, normal breaking and making currents, fault current magnitude, service and environmental conditions. Conduct a simplified inspection every 6 months and a comprehensive inspection annually.

During routine inspections, confirm whether the breaker has been drawn out to an isolated position or moved out of the draw-out cradle. Always seek help from a professional if you encounter any uncertainties or feel that the task is beyond your expertise.

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