Planning for future - compressor outlet

[katit]

I'm wiring stuff in garage and planning for 240v outlet for compressor. Should I just go with 12ga 20A wire? I think in future I may get 20cfm compressor capable of sandblasting/spray painting and wonder if those need more juice?

Another question about disconnect. Is there switches for 240V? Compressor will be in a basement and I would like to switch it off when not in use in case there is leaks or something so it doesn't kick in at night.

Or maybe I can wire automatic shutoff into garage somehow so I can just switch it off on regulator just like I can do it at compressor?

 

[JBurgess]

I'm wiring stuff in garage and planning for 240v outlet for compressor. Should I just go with 12ga 20A wire? I think in future I may get 20cfm compressor capable of sandblasting/spray painting and wonder if those need more juice?

Another question about disconnect. Is there switches for 240V? Compressor will be in a basement and I would like to switch it off when not in use in case there is leaks or something so it doesn't kick in at night.

Or maybe I can wire automatic shutoff into garage somehow so I can just switch it off on regulator just like I can do it at compressor?

A 20 CFM compressor is likely to be a 5 HP. I would go with 8ga 40A.

Yes there are switches for 240V. If your compreeor has a contactor there are other posibilities. See this thread:

http://www.garagejournal.com/forum/showthread.php?t=55458

If you can give more details, such as the compressor you want to get and type of wiring you are planning on, it will help on getting more responces.

 

[katit]

Here is what I have:
1. Basement and unfinished attached garage
2. Desire to have compressor in basement
3. Husky pro 26gal compressor that runs off 110 but can be wired 240
4. New 100A panel and need to wire everything so I can drywall.
5. Desire to control compressor inside garage keeping compressor in a basement.

So, it's not about "what I'm going to get" it's more about planning. I just research on possibilities as air line will be coming from basement and electric line going to basement. I'm not sure what I'm going to get..

"IF" I will upgrade compressor - it's going to be something decent in $1000-2000 area and if there is different kinds/controls I would like to know what's available and be prepared for it wiring-wise. It's no big deal right now to throw additional 10ft wire down to basement if I can utilize it later. I will just plug it in a box and let it be til I update. I can keep my current compressor wired of 110 outlet or I can start using new 240 outlet right away.

 

[sberry]

Most home comps run from a 10 wire, the 7.5 ones require 8, they are the ones above 20 cfm.

 

[JBurgess]

Most home comps run from a 10 wire, the 7.5 ones require 8, they are the ones above 20 cfm.

5 HP motor 230 volt 28 amps Table (430.248)

28 amps x 125% = 35 amp min conductors (430.22)

So I get #8 conductors if using romex.

Or you can plug into a online calculator:
http://www.electrician2.com/calculators/motor_ver_1.html

 

[rodnok1]

If you don't mind running wire to the garage get something like this.

 

[JBurgess]

A 5HP switch that looks like a light switch:

http://www.onestopbuy.com/leviton/MS302-DS-38461.asp

 

[Falcon67]

I would run the #8 through a disconnect to a junction box near where the compressor would sit. Then out of that, you could drop a pigtail of the appropriate socket and wire size fro what you wanted to connect at the time. You'd be good up to mondo compressor size and could just update the connection end depending on what you had hooked up at the time. Disconnects are cheap - sometimes cheaper than high current switches. One issue I'm going to fix on my run is the shutoff - I put it by the compressor. Nice. Except I leave and always forget to turn it off. So I'm going to move it over to the light switches next to the door. On the way out - click, click, click, push - lights and compressor off.
Neatly wired - off in the corner:

 

[Door-Man]

A 5HP switch that looks like a light switch:

http://www.onestopbuy.com/leviton/MS302-DS-38461.asp

that looks nice. much more aesthetically pleasing then a large disconnect box.

 

[katit]

Yes, that switch looks very good.

 

[sberry]

430 would be for true 5 hp motors but most of these comps are not. I believe they list the electric requirements in the owners manuals. An 8 wire isn't going to hurt anything for sure, in this case the distance is short, not much cost difference either.

 

[GR8Dane]

I'm in a similar situation it sounds like.

I had my smaller 110v compressor located in my basement connected to a regular household outlet. Half the time it wouldn't start up due to limited amps.

While upgrading the garage the electrician put in a separate circuit from my main electrical panel to the compressor with the intent of having it available for 220 later. He also put an industrial switch out in the garage so I can turn it on and off without going downstairs. Right now it is still wired with a 110v faceplate but as soon as I install the new compressor he will swap some wires around onto a new faceplate and I'll have 220. I'm no electrician so I don't know exactly how that works, but he wired it all up so I'm good for now and for the future.

 

[JBurgess]

I had problems with a switch being left on when not needed, so installed a P & S TMHWL-ECC night light next to it. Might help to keep from forgetting to turn the compressor off. The one with the light sensor was cheaper, so I just colored over the sensor with a black sharpie. It's 110 volt so you will need a neutral up to the switch.

 

[katit]

Thats sharp! I like it.

 

[katit]

Is there "standard" switches for #8 gauge available? Or they don't go above 30A?

Also, is #10 30A and #8 40A?

 

[JBurgess]

40 amp switch:

http://www.onestopbuy.com/leviton/WS402-9064.asp

 

[katit]

If I use that switch along with a light in a box, is it OK to use 2 gang box for #8 wire?
For the light - I will have to bring neutral to the box. Can I bring 8-3 from panel into box and then take 8-2 to the outlet? Is that OK?

 

[JBurgess]

If I use that switch along with a light in a box, is it OK to use 2 gang box for #8 wire?
For the light - I will have to bring neutral to the box. Can I bring 8-3 from panel into box and then take 8-2 to the outlet? Is that OK?

This switch will accept #8 solid:

http://www.electricsupplyonline.com/prod/cooper-motor_controls/ahmc240c_w011444.php

Be sure your 2 gang box is extra deep for bending room for the wires. A 4x4 deep box with a plaster ring wii give some more room.

yes 8/3 from the panel and 8/2 to the compressor.

 

[katit]

Just got #8 cable and it's not solid. Is there any switch that will accept it?

Also, another question. I have 6-2 for welder outlet. Will oversized single box (22cu) be enough? It is OK to use those boxes for such outlets?

 

[JBurgess]

This switch will accept #8 solid:

http://www.electricsupplyonline.com/prod/cooper-motor_controls/ahmc240c_w011444.php

The switch will accept #8 standed also, I mentioned solid because some are listed for #10 solid or #8 stranded with ring terminal.

What type of cable are you using?

 

[katit]

The switch will accept #8 standed also, I mentioned solid because some are listed for #10 solid or #8 stranded with ring terminal.

What type of cable are you using?

Copper NM with solid ground(black/red stranded).
It's black colored wire from HD. 8-2 for future compressor line and 6-2 for future welder.
I will use 30A on one and 40A breakers

Wires will be stapled to 2x4 frame and shitrocked.

Does it sound ok?

 

[MrMark]

You won't get that 6 wire in a little single gang box in a million years. You need a 5S box and a ring. And, that will be tight. 4S is too small also.

 

[katit]

Pardon my ignorance, what 5s box look like? Can I put it inside wall?

Also, for 8-2 wire, what box to use in a basement to mount it to concrete unfinished wall?

 

[MrMark]

5S is the next size up from 4S. It's like 4 11/16 square and 2.5 deep, or something close to that. You can mount it in the wall or exposed with conduit.

 

[sberry]

6's will work in a 4 square box but you need raised cover, I use a deep box also, I believe it is 2 1/8.

 

[ket-tek]

Disconnects are cheap - sometimes cheaper than high current switches. One issue I'm going to fix on my run is the shutoff - I put it by the compressor.

Do you have a link or know the model of the switch you used in this pic? I like the red/green on/off push button style like that..

 

[MrMark]

6's will work in a 4 square box but you need raised cover, I use a deep box also, I believe it is 2 1/8.

why cause the guy problems? Why undersize the box? Isn't bigger always better with boxes and wires? Is the extra .23 cents really going to break him? It just might save him some cursing. I know from experience that getting 3 6 THHN in a 5S box is really hard. It would be really really hard in a 4s.

 

[noslo04]

The referenced 4s and 5s boxes seem to the metal type. What is the equivalent size in a blue plastic old work box? Is it common practice to use a raised cover with a plastic box?

 

[MrMark]

you can't put wires this big in plastic boxes.

 

[katit]

Guys, as far as boxes I don't care about $$ I'm rich enough to afford those
What I _do_ want is this outlet to be more or less pleasing authetically. So, making it flush with a wall would be perfect.

 

[sberry]

The reason to use a 4x4 is that the covers fit. Its what they were made for. Also 2 6's and a 10 is what is required.

 

[Falcon67]

Do you have a link or know the model of the switch you used in this pic? I like the red/green on/off push button style like that..

It's a Grizzly part - H8238: http://grizzly.com/products/110-220V-On-Off-Switch/H8238

It's rated at 20 amps @ 220 but (IMHO anyway) you'll not get more than a 12 gauge wire on it. The screw terminal in the back are really small.

 

[MrMark]

The reason to use a 4x4 is that the covers fit. Its what they were made for. Also 2 6's and a 10 is what is required.

He's not doing exposed work and that "cover" you are refering to. And, I am sure there is an exposed work "cover" for a 5s box.

He's putting it in the wall and needs a 2 gang mud ring. They make those for 5S boxes all day long.

 

[JBurgess]

I think the OP wants something like this, but 40 years newer:

Parts needed plus a cover and a romex clamp:

 

[oleguy]

I think the OP wants something like this, but 40 years newer:

Parts needed plus a cover and a romex clamp:

that is what i wire range outlets with.6/3-gnd.with 2x4 framming use a 5/8"mudring.also fyi #6 wire takes 5.0 cubic inches of volume per wire.so a 6/3=gnd will be 15 ci for the #6 plus 2.50ci for the #10.or a 17ci box min.a 4x2 1/8 box is 30.3 ci.don't forget if you use a metal box you need to ground it.there is a small hole in the back of the box with 10-32 threads.get some green ground screws.

 

[MrMark]

the 10 wire is too big for the ground screws. You need a small lug kit that screws in to the ground screw hole. The 10 wire won't stay under the green ground screw securely.

Do it right. The reason for the biggest box you can use is because it makes life easy and there's no good reason not to use it. As with all things electrical, bigger is better and not that much more expensive usually. Only fools try to save a dime on electrical stuff.

You need to leave 8 to 10 inches of wire sticking out of the box and fold it accordian style back into the box. That 5S box won't seem very big when you try to make up the outlet.

 

[sberry]

I was thinking about this thread for a minute. I am a believer in a bit of overkill but at some point things that are adequate are fine. First we have wire a couple sizes bigger than needed to run almost anything found in this type of garage and now we figure out that a box almost twice past legal isn't big enough for some reason so lets debate and confuse someone trying to do a simple job even further. I say skip the green screw and the little lug and since the ground wire is attached to the yoke of this self grounding outlet to screw it to it and call it a day. I bet we can come up with at least a couple code quotes that don't even apply???

Do it right. The reason for the biggest box you can use is because it makes life easy and there's no good reason not to use it. As with all things electrical, bigger is better and not that much more expensive usually. Only fools try to save a dime on electrical stuff.

Just out of curiosity how many of these have you done? You find odd ball parts for each one? I cant recall ever seeing this device mounted in a 5s boxe, I am sure its been done, just don't remember seeing one in a thing designed primarily as a Jbox for larger conduits in industrial settings, never one in residential work to mount a device.
I could be wrong but don't remember the box store selling anything but a blank cover for them.

 

[Norcal]

I was thinking about this thread for a minute. I am a believer in a bit of overkill but at some point things that are adequate are fine. First we have wire a couple sizes bigger than needed to run almost anything found in this type of garage and now we figure out that a box almost twice past legal isn't big enough for some reason so lets debate and confuse someone trying to do a simple job even further. I say skip the green screw and the little lug and since the ground wire is attached to the yoke of this self grounding outlet to screw it to it and call it a day. I bet we can come up with at least a couple code quotes that don't even apply???

The grounding conductor needs to be bonded to the box & a ground screw works just fine w/ a 10 AWG solid CU conductor.

 

[MrMark]

I just did one the other day. Exactly the same. 6 gauge wire and a 5S box. The ground screw does not work, it is not big enough and it was not intended, nor designed, for anything over 12. It slips off if the ground is pushed on when the wires are folded back in. It was not designed for 10 gauge wire.

I don't buy electrical supplies at a "box" store, whatever that is.

I haven't described anything that is remotely "odd ball." It may be odd ball for Home Depot but it is not "odd ball" for any decent electrical supply.

How do you know a ground screw is just fine. Have you ever actually done one of these? I take it you are an inspector of some kind. Have you actually made up a 240 plug with the described wires?


I don't go by what is "legal" as being the be all and end all as some here do. Legal is the bare minimum. Legal is not synonomous with smart or practical or common sensical. A bigger box is just smart, plain and simple. There is no downside, only upside. Legal is not even a consideration there. If there was a 6S box, I would use it. The boxes are never big enough for me.

 

[Norcal]

I just did one the other day. Exactly the same. 6 gauge wire and a 5S box. The ground screw does not work, it is not big enough and it was not intended, nor designed, for anything over 12. It slips off if the ground is pushed on when the wires are folded back in. It was not designed for 10 gauge wire.

I don't buy electrical supplies at a "box" store, whatever that is.

I haven't described anything that is remotely "odd ball." It may be odd ball for Home Depot but it is not "odd ball" for any decent electrical supply.

How do you know a ground screw is just fine. Have you ever actually done one of these? I take it you are an inspector of some kind. Have you actually made up a 240 plug with the described wires?

Because I have done it many times with ease, a 10 AWG solid CU EGC will loop around a grounding screw quickly & w/o any issues .