I built very simple circuit which allows turning on/off using microcontroller low voltage signal. To have it protected I've decided to add circuit breaker. Since it consumes 120W of power (around 0.5A of current) I've chosen a 1A circuit breaker with C tripping characteristic. The reason I chose the C-curve is that the device contains a pump (which is an inductive load) so there might be some spikes. I've measuared these spikes with a multimeter. The maximum instantaneous current would be 1.74A.
The problem with the setup is that when I turn on the circuit breaker it trips. It doesn't always trip always. Sometimes it works as expected. I thought the problem is with the circuit breaker, but replacing one didn't help.
Could anyone suggest what can go wrong in such a setup? For sure current doesn't exceeds 1.74A (AC RMS) which is not enough for instant tripping. Except the multimeter can't measure such a short current spikes, might be worth checking with oscilloscope.