For sizing conductors, you do not use the nameplate amps of the motor; you use the horsepower rating.
Using table 430.248, and the nominal voltage you plan to use, you use those amp values for your calculations.
If the motor is to be run 'continuously' (for over three hours), then the 1.25 multiplier applies.
The motor nameplate amps may be used for the sizing of your fuse or breaker ... and is certainly used for selecting your "heater" sizing.
The table values are, I'm convinced, based upon the worst 1930's motors they could find. I have yet to see a motor that, for the horses, required anything like the amps the tables specifies. I think the NEC is trying to 'worst case' your motor replacement.
[This message has been edited by renosteinke (edited 03-03-2007).]
