3 phase current cancellation

[radioengr]

I hope this is not a dumb question- I am working inside equipment that runs on 208V 3-ph power. There are differing loads on each phase. I have come across power budget calcs by previous engineers that show "phase current cancellation" of the form (Ia-Ib)+ Ib/sqrt2
Can someone explain the underlying theory?
tx

 

[sslobodan]

Well it depends on the simultaneous factor of your gear considering that 1/sqrt(2) is 0.7 I think he just wanted to make scientific approach to his calculus to a boss. General factor you take in consideration is 0.8 or less, (If you have 2 pumps work and reserve p. fact. would be 0.5 of total power) so recalculate it because those factors can run from 0.4 till 1