Breaking capacity of a circuit breaker is usually expressed in:

A circuit breaker should be rated with short circuit making capacity. As the rated short circuit making current of the circuit breaker is expressed in peak value, it is always more than rated short circuit breaking current of the circuit breaker.

Making capacity of a circuit breaker is equal to 2.55 times symmetrical breaking current.

Breaking capacity is always expressed in rms value.

Both breaking and making capacity are generally expressed MVA.