Resumen electricos

MCA (minimum circuit ampacity) = WSA (wire sizing amps) = your wire ampacity must be this big or larger.You may need a larger size (for voltage drop or energy savings or whatever) but you cannot use a smaller size.

FLA (full load amps) = RLA (running load amps) = use this for load calcs.If you don't have MCA/WSA data, then this will get you in the ballpark for feeder size (but may ultimately be wrong).

MOCP (maximum overcurrent protetive device) = maximum breaker or fuse rating.You may see some equipment with a "maximum fuse rating" -- in that case, you MUST use a fuse (it can ALSO have a breaker in the circuit, but a breaker alone won't cut the mustard).The MOCP rating will often be larger than the MCA -- that might seem strange to you, that the fuse/breaker is bigger than the wire, but that is OK and 100% per code.You can size the wire bigger if you want to or that makes you feel better, but you are not required to per code or UL.

LRA (locked rotor amps) is what a motor will draw with a locked rotor, which will very nearly equal what it will draw during starting.This will usually be about 700% of full load amps and will last for about 6 seconds.You use this to calculate motor starting voltage drop.Code only requires you to calculate motor starting voltage drop for fire pumps and very few other specific motor types -- but practially, if your voltage drops below 85% or 80% of nominal voltage, your motor may refuse to start.For short runs (say, less than 300 feet at 480v), motor starting probably won't be an issue for you.

Your MCC would generally be sized based on FLA.125% of largest motor FLA plus 100% of all other smaller motor FLA would be a good minimum MCC size (and would be in accordance with NEC 430 motor feeder sizing requirments).

See NEC 430 for motor & motor feeder requirements general to all motors.

See NEC 440 for motor requirements specific to HVAC motors.The MCA/MOCP questions above are specific to HVAC motors and are covered in NEC 440.