Motor feeders and overcurrent protection

[dsbrown]

I am trying to get a handle on the proper sizing for overcurrent protection and conductor size for single motor loads and multi-motor loads. As I understand it (refering to NEC 430.22) short time duty motors rated at 30-60 minutes, the conductors would need to be sized for 150% of the motor FLA. Then refering to NEC 430.52 the overcurrent protection device (Inverse time breaker) would be 250% of the motor FLA. The question that I have is that on its face the conductors are undersized for the overcurrent protection device. Is this an acceptable configuration given that this is a motor load and the requirements of these code sections have been met? Or does the conductor for a single motor load need to be sized for the breaker protecting the motor (and only the motor)?

Thanks in advance for any help

 

[bphgravity]

The branch circuit conductors supplying a motor or motors are protected by overloads. These overloads are either integral to the motor or a component of the controller. The branch circuit overcurrent device protects the branch circuit’s conductors from ground-faults and short-circuits only.