Multiwire branch circiuts

[j9DuBois]

I've got a question.

So lets say we have three circuits on a three phase panel and the 3 Cts share the same neutral, with 210.4, the handle tie is supposed to trip all three if one becomes overloaded, now what if...
a maintenance person installed a split breaker so now it is the "B" or the second breaker of each of the split breaker on the three phases, they installed it this way because there was not enough room in the panel and the panel is in an old building. What do you do? get a bigger panel, retrain staff/

 

[LarryFine]

So lets say we have three circuits on a three phase panel and the 3 Cts share the same neutral, with 210.4, the handle tie is supposed to trip all three if one becomes overloaded,

Actually, the internal common trip is supposed to trip the three poles. The tie handle is for manual operation.

now what if...
a maintenance person installed a split breaker so now it is the "B" or the second breaker of each of the split breaker on the three phases,

This you'll have to re-phrase.