air compressor breaker size

[Mark Bolton]

It's on a plug. I wanted to use the same outlet for my welder. I.dont care about the warranty.

Then just do it? Why bother asking? Semantics? Your thumbing your nose at any specification which is completely acceptable as you own the compressor. If you want to do it, own it, dont ask about it... do it. You've said youve read about numerous people with no problems? Why tiddle (trade tiddle for the willow that grows in wetlands) foot into it... just do it and be done with it? This isnt federal government bureaucracy where there needs to be 3500 channels of conversation about how to slide a paper clip onto a sheet of paper. You own the compressor, you disagree with the manufacturers spec,... Just do it?

[Mike Cutler]

The NEC stops at the receptacle/plug interface.

[Bill Yacey]

The NEC stops at the receptacle/plug interface.

Likewise in Canada. But there is a definite contravention of the electrical code to put a 50A breaker on a circuit that was ever only intended for 30A. This creates a potential fire hazard.

[Mark Bolton]

Likewise in Canada. But there is a definite contravention of the electrical code to put a 50A breaker on a circuit that was ever only intended for 30A. This creates a potential fire hazard.

When any component in that compressor goes kaput.. its going to draw more than an adequate amount to trip the specified breaker. Why in the world you would think a company that as an annual revenue, and likely single machines, that exceed your entire lifes net-worth, would jeopardize their entire operation and reputation for a forum arm-chair quarter back session is beyond reality. They undoubtedly have EE's on-staff that lock it down easily.

If you dont like their power supply call out dont buy their product? Wouldnt that make sense? Or just ignore their spec's and do as you please and dont whine about it.

Seems pretty straight forward, black and white, to me...

[Travis Conner]

Mark I was just curious as to the reason for requiring the 50 amp breaker when a 30 amp will work also. I used a 50 amp breaker as specified in the manual.

[Frank Pratt]

I don't know about in the U.S., but in Canada it would be illegal to install a 50A breaker if the plug / receptacle on the compressor is only rated for 30A; as well, the circuit wiring would have to be AWG #6 for 50A.

That's an over simplification. The conductors in a motor circuit must be at least 125% of the motor FLA, and a circuit breaker for that circuit can be up to 250% of the FLA. In at least some jurisdictions, if the motor connects to the circuit (where the plug/receptacle also serves as a motor disconnect) via a dedicated receptacle, then the plug & receptacle only have to 125%, same as the wire.

[Mike Cutler]

Mark I was just curious as to the reason for requiring the 50 amp breaker when a 30 amp will work also. I used a 50 amp breaker as specified in the manual.

Travis
The "simple answer", and I promise you that it can be anything but simple", is that if you were to permanently wire that machine per the manufacturers instructions, you would need to install conductors rated for 125% of the FLA/FLC. This would be a "nominal" 28 amps, not counting service factors. This is where Quincy is getting the 50 amp breaker requirement. Will your air compressor ever draw ~28amps? I hope not, at least not for more that 20, or 30 milliseconds.
Sizing motors, breakers, conductors, and overloads, is not a straight forward exercise. There is no "simple chart".
You are "plugging" your air compressor in, so you don't have to concern yourself with the breaker/conductor sizing issue if you do not want to. It's no different than plugging in a vacuum cleaner.
Will a 5hp motor operate on a 30 amp breaker? Sure it will, but there could be some long term reliability issues. I have a 5HP, 35lb, commercial washer that I plug in to wash horse blankets. When that thing hits the spin cycle, it's 300lbs of metal, 30 gallons of water,and a wet horse blanket, That's more load than an air compressor is ever going to present. ( Damn thing weighs 850 lbs dry!!!)