Motors and the NEC

SIDEBAR 2: FLA Vs. FLC

The nameplate full-load ampere (FLA) rating is the current the motor draws while producing its rated horsepower load at its rated voltage, based on its rated efficiency and power factor. The current the motor actually draws depends on the actual voltage at the motor terminals and the load the motor is trying to drive. The current increases if the load increases or if the voltage decreases.

Caution: To prevent damage to motor windings from excessive heat (caused by excessive current), never load a motor above its horsepower rating, and be sure the voltage source matches the motor’s voltage rating.

The full-load current (FLC) tables are found at the end of Art. 430. In general terms, the permanent wiring installed for motor circuits is sized based on these tables, which are intended to be large enough for any motor design of a particular horsepower rating.