Motor Overload, Conductor & Short Circuit Protection

[LMAO]

Hi,
Just a quick question about motor overload, conductor and breaker.
The way I understand it, for breaker (fuse) and conductor you should always pick the next larger size; but for overload, you should always pick the next smaller size, correct?

So, for a 3 phase, 25HP, 230V, 62A name plate FLC, 1.00 service factor:
conductor: greater than 68 x 1.25 = 85A minimum.
overload: not higher than 62 x 1.15 = 71.3A, so 70A.
inverse t short circuit breaker: greater than 68 x 3 =205A, so 225A.

is this correct?
thanks

 

[david luchini]

The maximum inverse time c/b would be 250% of full load current from the tables, using the next standard size up. So 175A would be the max.