Common trip/independent trip behaviors confusion

[Flicker Index]

This one is crystal clear. The middle is a 2P circuit, if something happens to either, these two trip together as a pair and they're switched as a pair.
The outer two are switched and tripped independently. This unit is equivalent to one 2P common trip + two 1P breakers.


But what about this one? They're meant to provide two pairs of 2P circuits, but labeled "non common trip". Does that mean if it's feeding a split duplex fed MWBC, a fault on one doesn't trip the other half, but to reset it, both has to be turned off briefly to be turned on?


This one too is kind of confusing. I can't tell if the middle two trip together or not.


This too is confusing. If there is a fault in any pole, does it mean all four trip together?

Perhaps it has to do with the way they're manufactured. The non common trip looks like they're two sets of duplex breaker sandwiched together with a handle tie and riveted together but the same as installing them side by side with a handle tie with the only difference being shared rivets. You seldom see 2P, handle tied, independent trip breakers.

 

[LarryFine]

"Internal common trip" affects "only" automatic operation; the handle ties affect "only" manual operation.

"Common trip" means there is an internal link between the poles that do not depend on the handle ties.

Otherwise, two independent, tied handles may or may not trip together, depending on the tie's stiffness.

 

[Electromatic]

Not that I've opened one up, but I would assume any poles tied together from the factory would have a "common trip" not dependent on the handle ties. I think part of what the labeling is intending is that, for example with the "quads" that consist of 2 - 2P handles, the inner 2P is independent from the outer 2P.

 

[electrofelon]

Does anyone make a quad with the outer two poles common trip? I see breaker #4 says "common trip" but it's not really clear which poles it is referencing.

 

[Electromatic]

I would say, based on the lines drawn between the poles, on breaker #4 and the others, that where the outer poles are tied together, they are common trip. (Not necessarily because of the handle ties.)