Feeder circuit protection vs motor branch circuit protection - OCPD size mismatch

[Tip DS]

Have a control panel rated for 53A, where inside is a motor branch circuit protected for 90A via Class J fuses. If the up-stream circuit breaker will presumably be a 60A, won't it trip during motor inrush before the 90 fuse ever comes into play?

I understand the motor branch circuit OCPD is sized at 175% to accommodate inrush, but... how does the upstream breaker accommodate the inrush? If that 60A upstream breaker can accommodate the inrush, why isn't the motor circuit also sized the same? I'm trying to wrap my head around why this makes sense.

Further, since I'm using conductors rated for 65A, shouldn't I have an OCPD somewhere in my control panel protecting them at their rated ampacity?

 

[ptonsparky]

I’ve seen drives that want class J ahead of them with a max size way more than is required to start the motor. I believe it has to do with the way they were tested. There is another thread on going about available fault current and SCCR.