I am trying to understand the advantages of using a 2 pole circuit breaker. I mean when the 2nd pole is used in the Neutral line in a single phase 230VAC system. Normally they cost more so they must have some advantages over the single pole circuit breaker. So please explain to me the actual advantages of using 2 pole circuit breakers in a 230VAC L and N lines.
The answers I found are mostly related N.American electrical systems which are 120 or 240VAC, so those are different than European systems. I also know there are regulations to use them depending on the installation area and the type of protection sought but I want to given the option of choosing one, which one should I be using.