What is meant by common trip as it relates to a 2 or 3 pole breaker?
Does a handle switch trip both breakers?
Miniature Circuit Breaker
QO Circuit Breaker
This means the 2 or 3 poles are linked internally and if any pole trips, they all open together.
Single pole breakers linked externally with a handle tie are not common trip. One breaker (pole) tripping does not trip the others.