Iwire:
Of course he is right the current will never divide perfectly evenly.
I would like to know how the other would not open fairly quickly at over 200% it's rating and if it did not open the safety hazard that would create.
So if we consider the possibility of uneven loading, even 2 breakers with identical curves, would be operating at different points on their curves. So the O/L condition might be trailing off as the first breaker is tripping. The 2nd breaker wouldn't trip. Now you have a 200A service instead of 400A and wouldn't know it. I don't see it as a safety hazard as much as a nuisance. But why wouldn't you tie them together if you were going to use them in place of 1 breaker? Can you imagine how tightly individual breakers would have to be inspected to ensure a match along the entire curve? Considering I just got an Agastat that didn't have its mounting holes tapped, I don't think I have that much confidence. User adjustments on the breakers would make things really interesting.
Joe
[This message has been edited by JoeTestingEngr (edited 07-01-2006).]
