Wiring in cutoff switch/box for future compressor

[Jim O'Dell]

I'm trying to finalize my wiring, and hopefully I can turn the electricity on by the end of next week. (I'm taking 2 days vacation that weekend!) The wiring I have for my future air compressor is just capped off at this time. I'm sure it needs to be in a box, and I'm guessing it would need some sort of cutoff, like the A/C cut off connections. I'm wiring for 30 amp with 10-2 w/gnd wiring in place, I'm figuring a 5 hp compressor will be the most I will put in. What are the best ways, and the acceptable ways, to do this in general terms? I would like to get parts while in town after work to save some gas. Thanks! Jim.

[Tommy Curtiss]

Just like you said,,go get a a/c disconnect from home depot,,,when you set your new compressor,,just run some flex to it and your done,,,,Tommy

[Kent Fitzgerald]

Jim, the compressor may come with a cord and plug set, or it may be intended for direct wiring. Without knowing exactly what's needed, I would just mount a utility box, terminate the cable in the box with wire nuts on the individual conductors, and put a blank cover plate on it.

[Bill White]

What Kent said, and I have my compressor also switched. I have a fear of some wierd occasion when the comp would spring a leak and run for a day w/o stop. Not a pretty thought.
Bill

[Jim Junor]

I used Leviton MS302 30amp Motor Starter switches to switch all my 20 and 30 amp 220 circuits. Hubbell has them as well but the Leviton switch fits in a regular box while the Hubbell is too wide. I think they go for around $20 or so.

[Tyler Howell]

What Kent said, and I have my compressor also switched. I have a fear of some wierd occasion when the comp would spring a leak and run for a day w/o stop. Not a pretty thought.
Bill

A magnetic switch or a disconnect will serve you well, even a dedicate circuit breaker.
The collapsing EMF field will damage the contacts of lesser switches.
I installed a pilot light that I can see from the house if power is applied to the compressor ( had one of those leak things years ago )

[Jim O'Dell]

Thanks for the replies. I bought the SquareD A/C cutoff on the way home last night before I saw several of your posts. I'm hoping that since it is rated at 60 amp that it won't be a problem on a 30 amp circuit. It is not fused, so there shouldn't be any implied circuit size. Is my thinking right there? I couldn't find any 30 amp units. Thanks again! Jim.

[Tyler Howell]

You are just using it as "a switch" local code permitting you'll be AOK!

[Chris Padilla]

I actually wired a 24-hour mechanical timer (used to run my pool pumps) to my compressor to prevent those "wake up with your heart pounding" 2 AM kick-ons that used to happen! No more!

[Ken Garlock]

Well, when we built, I told the electrician that I wanted a 30A 240V outlet for a compressor. That is exactly when he installed. It is of the electric range type. The separate disconnect is not required, at least in Collin County. If you want to disable the power, use the breaker in the distribution panel.

My compressor is a 5 HP 40 gallon Ingersoll Rand 2 stage. I comes from the factory with a power switch built in, all you is add a power cord and plug. I used a 10 Ga. air conditioning cord after I cut off the female plug. The cord plug also provides a manual disconnect at the receptacle. The compressor has been working for 4 years without complaint.

[Jim O'Dell]

Thanks guys!
Ken, It could be a couple years (or more at the rate things are going ) before I'll have the compressor. I wanted something I could terminate the wires in that would be safe and raise no eyebrows. The circuit breaker will be off until I have the compressor.
Chris, that's a great idea to keep the compressor off at night. Are those expensive? If so, I bet I could rig up a contactor for 22.00 plus a cheap(er) 110 volt timer to run the contactor. Hopefully I'll remember this when I get there!
Thanks for the confirmation, Tyler. That's exactly what it will be used for. May even have enough room in it for the above contactor!! Jim.

[Bob Michaels]

Jim, as I interpret your post, you just want to make a temporary (2 years) termination point for a 10/2 with ground romex wire coming from your panel. In the future this wire will power your compressor. Cheapest, easiest, and most sensible solution is to simply dead end this wire in a junction box with a cover. Wires will be wire nutted. This way you can make any device related decisions at the time you will put this circuit into use. You probably won't need a cut-off switch so why make that investment in a circuit that goes nowhere (for now). Hope this helps.