Article 440 applies to electrically driven air-conditioning and refrigeration equipment. The rules in this Article add to, or amend, the rules in Art. 430 and other Articles in the NEC [440.3(A)]. A key term to understand is “rated-load current.” This is the current resulting when the motor-compressor operates at rated load and rated voltage.
Each manufacturer has the motor for a given air-conditioning or refrigeration unit built to its own specifications. Cooling and other ch