ACB (Air Circuit Breaker) testing and service involve evaluating the performance and reliability of ACBs to ensure safe and efficient operation in electrical systems. Testing includes checking insulation resistance, contact resistance, and tripping mechanisms through primary or secondary injection tests. Service tasks involve cleaning, lubrication, tightening of connections, and replacement of worn components. These processes detect potential faults, ensure correct breaker operation, and maintain protection against overloads and short circuits. Regular ACB testing and service help prevent equipment failure, reduce downtime, and ensure compliance with safety standards in industrial, commercial, and critical power distribution applications.