Circuit Breaker Size for motor connection

[wcorbit721]

I'm trying to understand the correct size panel circuit breaker for a motor connection (air compressor). I have a 20hp air compressor (3-phase AC motor) with a FLC = 30A @460V. Based on 125% overload protection, I will be installing a fused disconnect with 35A fuses. I'm going to feed the disconnect from an adjacent 277/480V Panel and am trying to figure out the correct circuit breaker size. Is table 430.52 of the NEC the correct table for short-circuit/ground-fault protection? If so, what is the correct % factor and why? Thanks!!

 

[charlie b]

I am closing this thread in accordance with forum rules. This forum is intended for use by electricians and electrical contractors, inspectors, engineers, and vendors with their job-related duties. We are not allowed to provide how-to advice to persons who are not employed in this industry, or persons who do not perform electrical installation or maintenance as part of their jobs.