ECN Forum Forums Code Related Discussion NEC & other Code issues Air Compressor Nameplate

Re: Sizing overcurrent protective devices, disconnects and wire. 5 HP 230 volts, single phase bolted to the floor air compressor. The nameplate amps = 23. Using the proper table in article 430, amps = 28. My question is: Is the air compressor considered an appliance thus should article 422 be used? I used to always use the amps listed in the tables in article 430. However, I believe the air compressor could be considered an appliance and the nameplate amps could be used.

Frank,

Yes it is an appliance, but, look at 422.3:
"The requirements of Article 430 shall apply the the installation of motor-operated appliances..."
and 422.12(G): "Motors of motor-operated appliances shall be provided with overload protection in accordance with Part III of Article 430."
We use the nameplate for the overload (heaters) protection, and the tables from Article 430 for the short circuit and ground fault protection, and choosing the size of the conductors and disconnects.