What is symmetrical breaking current in circuit breaker?

Symmetrical breaking current in a circuit breaker refers to the maximum current that the breaker can interrupt under symmetrical fault conditions, typically characterized by a balanced three-phase system. This current is measured during a short-circuit event where the waveform of the current is sinusoidal and symmetrical, meaning that the positive and negative halves of the waveform are equal. It is an important parameter for ensuring that the circuit breaker can safely handle and interrupt fault conditions without damage. Understanding this current helps in selecting the appropriate circuit breaker for a given application.