Hi, I'm a new member, I'm an electrician from southern Scotland, I have worked for a firm here for 14 yrs doing mainly agricultural and light industrial repairs, and smaller installation jobs.
run the pump, and put on your clamp meter see what it's drawing. Check what your o/l is set at.
Is their a capacitor on the pump? If this is faulty it could pull the load up as well. If there's a bearing away in the pump this could also increase the load Also. If its lifting the mcb the pump...