What is meant by sustained overload and transient overload in miniature circuit breakers?
Sustained overload is overload that is continuous, or permanent. A resistive load is a good example. This is the kind of overload you get from simply plugging too many items into a circuit. Transient overload is overload generated by a reactive load, a momentary short circuit, or other temporary condition. An example of a reactive load is the compressor of an air conditioner starting. This kind of overload can be caused by a reactive load being added to an already moderately loaded circuit.