In the NEMA(NEC) code there is a procedure to size fuses, motor starters, and overloads knowing full load amps. How is this done using ohms law. Say full load amps is 2.6A which we have at work. We looked at the NEMA code and it said do 125% times 2.6A then 125% times that , but using ohms law what is going on? To know what fuse need, overload devices, etc? This NEMA shortcut in the end says use a 10amp fuse, but how know multiply by 125% using ohms law?
To size Fuses, we want to make sure that we protect properly against any short circuit, but do not "trip" on possible overloads. That is why the minimum rating should be above the Full Load ...
The solution determines how to multiple by 125% using ohms law for NEMA(NEC).