Originally Posted by kok328
All the industrial compressor I've worked with are 3 phase not single. They are also setup to run constantly with load and unload pressure points that keep a steady supply of air in the tank. Your unit should state the FLA and that will determine the amperage required.
This is NOT an "industrial" compressor. It is a P-C compressor with the word "Industrial" on it. There IS a difference.
Also, the ones you are referring to a pretty rare, at least around here. In fact I have never even seen one that runs constantly. Pretty wasteful IMO, I don't care how mush it is used.
First off, this is NOT a true 7.5hp motor if it is only a 30A draw. A "real" 7.5hp motor @ 240v single phase should be around a 38-40A draw.
This is probably one of those "developed HP" ratings, like Craftsman shop vacs have. We ALL know, there is no such thing as a 6hp shop vac with a standard 15A plug on it.
If the actual draw is 30 amps then DO use #8 wire and a 40 amp breaker.
There are MANY odd and special codes regarding motors. Read NEC Art. 430. Your head will spin.