Originally Posted by electures
FLA has to be sized from 430.247. I'm still curious about manufacturers instructions though.
In most cases, yes. But when dealing with compressors, especially ones that are marketed to consumers, I'd be willing to bet the farm that his compressor is NOT an actual 5 HP. It may be advertised as such, but if one were to take the actual amps of such a beast, one would be able to determine that it's more like 1½ actual HP.
Which would operate just fine on a 15 Amp circuit as stated elsewhere in this thread.
Without the nameplate information, we are stabbing in the dark here.
Tell you what: Next time you are out shopping at a place like Sears, or Lowes, etc. go have a look at their air compressors. Look for one that is advertised as 5HP in big letters on the signage. Then take a close look at the nameplate on the actual motor.
The nameplate will NOT state "5 HP" on it. That will be left blank, or have something stupid like "spl" or some other such nonsense on it.
Those manufacturers should be shot. They get their advertised 5HP ratings from the LRA of the motor, not the actual delivered hp from a running motor/compressor. And the regulatory folks who allowed this nonsense should be shot as well.