Plastic case circuit breakers have a plastic case rating current and a trip current, and since there is a classification, there must be a difference. The breaker case current rating is that of a large striker that can be mounted in a frame with the same basic dimensions as the plastic case. The breaker current rating is the current that can pass through the breaker for a long period of time when it is released, also known as the breaker release rating. There are a variety of current ratings for case construction classes within the same series, and a variety of current ratings within the same case construction class.

Moulded Case Circuit Breaker Shell Level

The case layer current can be understood as the current capacity of the circuit breaker, and the internal conductors of the circuit breaker are different in different cases. For example, a case 400 circuit breaker is not only larger than a case 250 circuit breaker, but also has a larger internal conductive element. The rated current of the release circuit provides the current protection range. For example: a circuit load with a calculated current of 170A can be selected for a circuit breaker with a case rating of 225A (some manufacturers only have 250) and a release (thermomagnetic release) current of 200A (adjustable range 160A ~ 200A). Of course, if capacity is taken into account, for example in the future, the capacity may increase to 320A and you can choose a 400A case circuit breaker and still choose a 200A release current in order to ensure the accuracy of the protection. In this way, only the circuit breaker or striker needs to be replaced, without changing the construction of the cabinet or the connection wires.

The TM1 series activities have rated operating currents, while the 100 case frame rating and the rated voltage and current data have 16A, 20A, 25A, 32A, 40A, 50A, 63A, 80A and 100A rated output currents. If we choose the DZ20-100/40 circuit breaker, that is in the normal development of the enterprise, when the current can exceed 40A, the circuit breaker will trip; if a circuit breaker control failure, when the current can not exceed 40A but less than 100A, the circuit breaker generally does not cause damage, the current problem still need to study the circuit breaker through; if no current time more than 100A, the circuit breaker technology is burned out.

The case current is also related to the specified heating current; in most cases the two values are equal, but there are exceptions. The approximate heating current is the high current at which the temperature rise of the components must not exceed the specified limit value when the switchgear is tested under the specified test conditions in an 8-hour operating regime. In the case of electrical components, this is generally identified as Ith. For switches with the same rated current, the operating conditions and working environment are different and the selected enclosure current is different.