Air compressor wiring

Aug 24, 2009 13 Replies

I am wiring my garage and am putting an outlet in for a "futre" air compressor to replace my small 110 unit. I bought 10/3 wire and plan to use a dedicated circuuit breaker. I also bought a flush mount 4 prong recepticle.



Can I use this for an air compressor?


Overkill. Most 220 volt single phase compressors work just fine on a 20 ampere circuit and they only need 2 12 gauge wires and ground. The cheapest standard plug and outlet is the one that looks like a normal 110 volt grounded outlet with one of the blades turned 90 degrees. See 6-20R and 6-20P on this chart: Be sure to wrap some red tape around the white wire on both ends to indicate that it's hot.

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Available at any decent hardware store.

Or better yet, hire an electrician. You still scare me.

stryped fired this volley in news:de36b302-c88c- snipped-for-privacy@a26g2000yqn.googlegroups.com:

You didn't say what sort of recepticle, so I'll assume you got one similar to a dryer outlet. It'll work, but you'd be better off with #

8 wire, 3-conductor plus ground.

A high-inrush 5HP compressor might draw 50 amps on start. Although #

10 will carry it without excessive heating, you'll get less voltage drop - even on a 30-50' run - with #8.

No biggie, though. I'm guessing you won't be going for a commercial grade and size of compressor, anyway.

LLoyd

I would suggest putting as big wire as you can afford. It amounts to just a few bucks, but lets you upgrade your equipment at will.

i

10-3 cable is plenty for a consumer 5 HP unit that's really a 3. But if you plan to buy a *real* 5 HP or 7.5 HP unitm, run 8-3 or even 6-3 to that spot, and use a 2-gang box.

Under the old codes you could use 2-conductior wire - but you had to cheat and connect any 120V stuff in the machine to ground to work. Clothes dryers, that's how you had a 120V Light in the drum and a 240V feed.

You are no longer allowed to connect "incidental loads" of 120V (like the work light or the timer motor) between one hot and the ground - it HAS TO go to a neutral wire.

And you might want to swap around the garage and put the air compressor outside in a shed (for the noise) and put your spiffy new drill press there in the corner instead, so... So put in a neutral wire everywhere and don't fret.

-->--

I am also running number 6 wire from a 50 amp breaker for my 225 Lincoln "buzz box". I guess if someday I had a real big compressor I could run off of that?

But first look at the lugs on your circuit breaker. It is pointless to buy wire larger than can be accommodated.

--Winston

Unless you can retrofit a bigger breaker later. I'd look at the biggest breaker I could put in the box, if I were burying a wire inside a wall. If I were burying a long run of wire I might go far bigger yet, figuring that a new box is cheaper than the cost of burying a new length of wire.

Never go wrong pulling 3 wire, and #10 will handle a REAL compressor.n a REAL 10HP

Winston fired this volley in news: snipped-for-privacy@news3.newsguy.com:

What 50A breakers do you have that won't accommodate #6 or #8?

LLoyd

Excellent question!

Whenever a Liberal utters the term "Common Sense approach"....grab your wallet, your ass, and your guns because the sombitch is about to do something damned nasty to all three of them.

You don't say how far away is the garage...and nobody else asked! Shame on them all.

Oh they'd accommodate #6 or #8 just fine.

Not #2 however.

:)

--Winston

On Mon, 24 Aug 2009 23:56:46 -0400, the infamous "Buerste" scrawled the following:

Shame on all the posts replying to this known troll.

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