26-258 (3) contradicts any inrush theory. We are allowed to use a 75 kva transformer for example where you would need 60 kva and size the conductors as if you had a 60 kva transformer. Seems that inrush is not considered as long as the overcurrent device does not operate. Not a good design practice sometimes.
Stating that conductors are required to be sized at 125% because it says so in 26-256 is not really answering the question of what exactly are we derating for. I'm sure there is a reason somewhere.
