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.
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.
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?
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.
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.
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