Molded case circuit breakers are the most common low voltage electrical components. Molded case circuit breakers can reliably switch on and off the rated current and automatically cut off the current when the current exceeds the trip setting. What do the parameters on the nameplate of the molded case circuit breaker indicate?
In: Rated operating current. Permissible current during long-term continuous operation, the current should not exceed its rated current during operation.
Ii: short-circuit instantaneous trip current. Exceeding this current immediately trips.
Icu: rated extreme short-circuit breaking capacity. The maximum short-circuit current that the circuit breaker can reliably break. After breaking this current, the circuit breaker cannot continue to carry its rated current. Just can't use it anymore.
Ics: rated operating short-circuit breaking capacity. The circuit breaker can continue to carry the breaking capacity of its rated current capacity. That is, the maximum short-circuit current that the circuit breaker can still reliably break. After the short-circuit current is cut off, the circuit breaker can still be used.
CAT A: Use category. A type of circuit breaker is generally used as the incoming line of the distribution cabinet or terminal circuit breaker. If there is a short-circuit fault, it is required to be quickly disconnected. Class B is mainly used as a low-voltage incoming main switch with short-circuit and short-time delay protection. It cooperates with lower circuit breakers to make current selectivity. In this way, it needs Icw (rated short-time withstand current) because it needs to carry a certain time. Short-circuit current.