NEMA 10-30r question

[byoungblood]

I'm adding an outlet in my garage for my 220v air compressor that should be showing up this weekend. For the sake of future use with other 220v tools (possibly a 180A MIG) that may require more current, I've installed a 40 amp breaker and 8/2 (being only 0.10/ft more than 10/2, it seemed to be a prudent upgrade) from the panel to the outlet.

I installed a NEMA 10-30r receptacle, however after doing some reading, there are some people admonishing to NOT wire this type receptacle with a ground as I have done. I can't determine simply because it isn't up to code and therefore should someone come back behind me would expect it to be wired differently, or if there is a safety issue here.

Am I OK with this setup as long as I know how it is wired, or should I swap it out for some other receptacle?

 

[mtne]

What is your FLA on your compressor and do you really want it protected by a 40A breaker? Does it have it's own overloads?

 

[byoungblood]

What is your FLA on your compressor and do you really want it protected by a 40A breaker? Does it have it's own overloads?

17A continuous, 20-22A peak (I think...the compressor has been sitting in my BIL's basement for the past 3 years). When I used it before it was on a 30A breaker if memory serves me right.

Perhaps I'm mistaken, but I thought the point of the breaker was to protect the wiring, not necessarily the equipment connected to it. My whole purpose of using the larger breaker was to be able to hook up a MIG welder sometime down the road.

 

[Charles (in GA)]

Problem is, you are using a 30 amp rated receptacle and protecting it with a 40 amp breaker. I would downsize the breaker to 30 amps and if it doesn't blow with the compressor, then you are OK.

Charles

 

[Norcal]

Problem is, you are using a 30 amp rated receptacle and protecting it with a 40 amp breaker. I would downsize the breaker to 30 amps and if it doesn't blow with the compressor, then you are OK.

Charles

He will have to upsize the EGC per 250.122(B). Use a 50A receptacle instead.

 

[Charles (in GA)]

What size ground comes in #8 Romex? In 250.122(A) it says that in no case is the ground required to be larger than the current carrying wires, I assume this applies to (B) which requires the upsizing.

Charles

 

[Norcal]

What size ground comes in #8 Romex? In 250.122(A) it says that in no case is the ground required to be larger than the current carrying wires, I assume this applies to (B) which requires the upsizing.

Charles

10 gauge.

 

[byoungblood]

I'll just swap it for a 6-50 then. I can't think of a time of when I'd run more than a 30A load so I went with the 30A receptacle and 40A breaker so it wouldn't trip all the time, but if the 50A receptacle would be more proper, then that's what I'll install. Thanks guys.

 

[Ironcrow]

I have several such high voltage/current receptacles in my house. They are all NEMA 14-50 instead of 6-50. I swap welder plugs to 14-50. I like to have 120v and 240v available for whatever future use. Just a thought.