What is the recommended wire gauge for service power on a small reciprocating compressor (7-15 HP)?

DISCLAIMER: The following information is a general guideline only. All electrical work should be completed by a licensed electrician and in compliance with local, state, and federal code.

The electrical wiring between the power supply and electric motor varies according to motor horsepower and other factors.

Install adequately sized power leads to protect against excessive voltage drop during start-up. Refer to the National Electric Code (NEC) for information on selecting proper wire size and securing electrical connections.

If you connect additional electrical equipment to the same circuit, consider the total electrical load when selecting the proper wire size. DO NOT UNDERSIZE THE WIRE.

If wire size information is not available, the wire sizes shown below can be used as a safe guide, if the distance does not exceed 50 feet (15.3m). For longer distances, consult an electrical contractor or the local electric company for recommendations. 

Also, be sure to install properly sized circuit protection. When selecting a breaker size for your air compressor, remember that the momentary starting current of an electric motor is greater than the Full Load Current. Time delay or “slow blow” fuses are recommended.   

See the table below for a guideline to breaker sizing.   

However, please refer to the National Electric Code (NEC) or consult with a licensed electrical professional to determine the proper circuit breaker rating required.