Motor FLA vs FLC

[Grouch]

I understand that motor FLA is used to size overload protection at the starter.

Motor FLC is used to size the conductors and the circuit breaker / fuses feeding the motors.

I also understand that FLC (found in the tables in Article 430) is usually greater than FLA, and is done so to be conservative and to try to capture all different types of motors at a specific horsepower and voltage.

What if you come across a motor whose FLA is GREATER than the FLC values from the Article 430 tables? Do you then use FLA to size the conductors and circuit breakers / fuses feeding the motor?

 

[Strathead]

First, C and A stand for the same thing. Current and amperage are synonymous, so I suggest you use table current and motor nameplate current as you words, it just removes confusion.

Second, I would use the tables for conductors and breakers, period. Not sure if you would run in to a motor with a higher nameplate value.

 

[Grouch]

First, C and A stand for the same thing. Current and amperage are synonymous, so I suggest you use table current and motor nameplate current as you words, it just removes confusion.

I know. But there is a distinction between FLA and FLC when it comes to sizing equipment. FLA is to size overload protection; FLC is to size everything else.

Second, I would use the tables for conductors and breakers, period. Not sure if you would run in to a motor with a higher nameplate value.

I ran into a fire pump whose nameplate FLA is greater than the FLC from the tables.

 

[don_resqcapt19]

I know. But there is a distinction between FLA and FLC when it comes to sizing equipment. FLA is to size overload protection; FLC is to size everything else.

I ran into a fire pump whose nameplate FLA is greater than the FLC from the tables.

The code has never used FLA. Those two terms were taught that way by some instructors, but the code only uses FLC. When I teach, I teach "nameplate" FLC and "code table FLC".
If I find a standard type motor where the nameplate FLC exceeds the code table FLC, I use the nameplate for everything.

 

[Grouch]

If I find a standard type motor where the nameplate FLC exceeds the code table FLC, I use the nameplate for everything.

That makes sense. I will use the nameplate value.

And noted on the 'FLA' term.