There is no general answer; for well behaved loads (e.g resistive, non hot-plugged) you could even think of using fast action fuses at the load side in addition with A,B curve circuit breakres - when affordable for the application. Any protection on the firmware side is mandatory to cut off the switching device when current exceeds expected value. Of course, we are talking about sampling the current on the shunt of the switching device as fast as possible, multiple times the mains frequency.