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Air conditioner overcurrent device

Question asked by on Aug 23, 2017

When sizing the OCPD for a hermetic refrigerant compressor, 440.22 states that the motor compressor branch circuit protective device shall be capable of carrying the starting current. A protective device not exceeding 175% shall be permitted, unless it is not sufficient to start the motor. This allows 225% to be used in this instance. My question is, if the manufacturer of the A/C installs a nameplate on the equipment that states a maximum branch circuit rating, should this section apply, or does the nameplate rating take precedence. I interpret this code to mean that if you were figuring the full load of the motor and compressor, you could use this section, but that you should always go by the manufacturers recommendation. Example. If the A/C says 30 amp branch circuit Max. can you install #10awg copper conductor on a 50 amp breaker. Note - There is a non fussable disconnect at the A/C location. I do not believe that you can and that this was not the intention of the code. Thank you in advance for helping with this question.