Maximum value of current that a circuit breaker. Breaker is rated at in=125A for ambient temperature 40°C well-appointed with appropriate calibrated overcurrent tripping relay. That same circuit breaker used at high value of ambient temperature. Frame size current rated, circuit-breaker can be fit with over current tripping units of changed current level setting range. Rated operational voltage- this is the power which the circuit breaker designing to work in normal conditions. Additional values of voltage is assigned to the circuit, parallel to distributed conditions.