Electical help needed wiring compressor

[V]

Ok i gotta wire up my new compressor but i gotta run the wire and setup for 220v. i have a basic idea but not enough to do it by myself, i have more common sense than that. I checked my main box and there is room for a double breaker, and i measured out that id need about 80' of wiring from the box to the garage,(35' from box to an exterior wall, then 35 outside in PCV conduit, then back into the garage for about 5'. Whats my next step? From what ive read so far with 220v, you run 4 wires: 2 hots, a neutral, and a ground. Is that correct? I want to install a sub panel in my garage then out to the compressor and a line for my lift for the future. The compressor manual states: 230V/1ph, FLA 16, Breaker size 30A. Anyone wanna help/ offer advice? I while back I called an electrician about running a 220 line and i was quoted "at least $1,000".

[BonzoHansen]

I have to look this stuff up, but I will tonight. I have a 60 amp sub box added in my garage. I'm going to wire the compressor off that.

I think someone here is an electrician. Maybe you can work deal running the wires, etc., and let him do the acutal hookups.

[V]

yeha i remember someone here was an electrician but i forgot who, maybe they'll pop in. ok i looked online some more, and for a compressor it appears i only need 2 hots and a ground. no neutral is needed for most compressors.

As of now, i plan on running 10/3 wiring (if i get the concept right, 10=gauge 3=wire, lol, give me a break im learning, lol.) Or would BX 10/2 be better? I figure 10 guage due to the 80' run, or is that overkill and 12/3 will be fine? I also decided just to run the wire to a single 220v recepticle, that way i can plug in the compressor, or unplug it for the rare times id use the lift.

My goal is this...(i will NOT actually do anything until im 100% positive so dont worry if i say something wrong) :-)
First, install a double pole 30A breaker in the main box in the basement.
Second, run the 10/3 wiring from the basement to the garage.
Third, connect the 2 hots from the new breaker and the ground to the new wiring i just ran.
Fourth, Connect the new wiring to the new recepticle box in the garage.
Fifth, get a 220v plug and short 10/3(or 12/3) wire to go from the plug to the compressor(less than 5 feet).

Do I have the right idea? lol

[V]

i went up to lowes to look around and get an idea of the wiring and available plugs etc. From everything i saw, 10/3 is for 30 amps, and thats what my breaker will be, so dont i want wiring rated for over 30amp in that case?(but i did read breakers flip at 80% of rating so i dunno) but anyways, I figure id use 8/3 wiring for the box to the garage(about 80 feet), and then i'd use a range/dryer surface mount recepticle and plug rated for 50A, then 10/3 wiring for about 5' to the compressor, so i can unplug it to use my lift eventually. Heres a diagram i drew up of how i understand it shoudl be run...





http://i32.photobucket.com/albums/d50/SmokingSS/wiring220v.jpg

[paul100]

I would check the compressor and what ever other tools you plan to hook up to this line first to see if it needs four wires or three wires. Most 220 tools that do not have a 110v control in them only require two hots and a ground. Witht he price of wire now it is worth checking into what wire you really need. What i just said is only if you are going to hook up a recepticle in the garage. If you are going to do a subpanel then there is a lot more involved. I dont think that picture you have is the best. They are saying to use 8/3 and 10/3 when actually it could be 8/2 and 10/2 wire. 8/2 and 10/2 actually have three wires where 8/3 and 10/3 have four wires.

[V]

ok, yeah then 8/2 and 10/2 will work, that was the other question i had, but since i looked and saw that its usually for timers, clocks, etc, then the 3rd insulated wire isnt needed.

[1QWIKBIRD]

ok, yeah then 8/2 and 10/2 will work, that was the other question i had, but since i looked and saw that its usually for timers, clocks, etc, then the 3rd insulated wire isnt needed.

I would put a small sub panel in the garage, if only to keep you from having to run in the house in case of blown circuit or some emergency. This will give you more flexibility in the future and additional safety. In the event something went wrong there is the potential to overheat/damage the buried wire before the circuit would pop. With a subpanel the buried line would be protected and the damage would be contained to the garage....This would be and extreme case, but ya never know.

For example I have a 60 amp breaker in my main panel, from there I have 8AWG leads going 125' (mostly buried, all in electrical conduit) to the subpanel in my garage. The main breaker in the sub panel is only 50 amps, and then I have my circuits broken down from there, the idea being that if something went really wrong, the subpanel itself would trip before the buried run overheated enough to trip the breaker on the main panel. Probably overkill, but fire sucks.....

this may not even be the best route, but running a 220V line 75' to receptacle to a 5' extension cord doesn't sound a whole lot different than a 80' extension cord, even with the 8/2 to 10/2??? Especially if ya start running a high demand tool like a D/A or any autobody tool which will keep the compressor working for extended periods....

Do your homework.....

Chris

[BonzoHansen]

Wires can't be too big (well, technically I guess they can they can). The breaker should be the soft point. Plus, the longer the run, the bigger the wire needs to be to accomodate the voltage drop inherent in a long run.

I just looked at the lead from my main (200 amp) service panel to my sub panel in the garage (60 amp). The run to my sub box is probably around 75 feet from box to box. The cable isn't marked, but it is rather sizable, I'd say 4 Ga.

[paul100]

For example I have a 60 amp breaker in my main panel, from there I have 8AWG leads going 125' (mostly buried, all in electrical conduit) to the subpanel in my garage. The main breaker in the sub panel is only 50 amps, and then I have my circuits broken down from there, the idea being that if something went really wrong, the subpanel itself would trip before the buried run overheated enough to trip the breaker on the main panel. Probably overkill, but fire sucks.....

Do your homework.....

Chris



I hope you mistyped some of that info. If you have 8 AWG running from your main panel then you should only have a 50 amp breaker there. Your wires are to small for a 60 amp breaker. 60 amp require a #6 wire.

[1QWIKBIRD]

Wires can't be too big (well, technically I guess they can they can). The breaker should be the soft point. Plus, the longer the run, the bigger the wire needs to be to accomodate the voltage drop inherent in a long run.

I just looked at the lead from my main (200 amp) service panel to my sub panel in the garage (60 amp). The run to my sub box is probably around 75 feet from box to box. The cable isn't marked, but it is rather sizable, I'd say 4 Ga.

Now you made go and check and your correct the leads from my house to the garage are 6AWG not 8AWG....

I just think putting a subpanel in offers another layer of protection and flexibility in the future...but really as long as its safe and it works all is well.

Chris

[paul100]

Now you made go and check and your correct the leads from my house to the garage are 6AWG not 8AWG....

I just think putting a subpanel in offers another layer of protection and flexibility in the future...but really as long as its safe and it works all is well.

Chris


A subpanel is the way to go. It is a little more complicated to wire then most people think. You need to have a subpanel that has the neutral wires isolated from the ground. No where int he subpanel can the netral and ground interconnect.

[BonzoHansen]

That is why I did it.

[V]

so..if i were to put in a sub panel... how would I go about it, I'd rather people explain to me instead of just saying "its complicated".
Either way, i need to get this wired this weekend.

Paul100, are u an electrician? and how would i run wiring to a sub panel, what gauge and all?

[V]

ok...so is this how to wire a subpanel...
install a 60amp breaker in my main box,
run 6/2 (w/baregound) wiring from that breaker to my garage,
mount a 4 space/8 circuit subpanel in garage,
connect 6/3 to new subpanel keeping neutral and ground isolated,
install double pole 30 amp breaker in new subpanel,
...then basically wire up my compressor as shown above using only 5' of 10/2 wiring...

Does all that sound close to correct at least?

I will not be staying in this house for that long, so adding future circuits is pointless, it will ONLY be used to run an air compressor, lift and possibly a MIG welder. For that reason, is why i was just going to run one recepticle.

[BonzoHansen]

The difference in price is very low - the additional box is a selling point (I don't know your deal if it is your house, parents' house, etc.). But a whole box is a no brainer. You will never regret adding it, only not adding it.

I looked again this morning, I pulled the cover off my sub panel - it appears to be 6 ga. with a red, black, white & ground.

[BonzoHansen]

Here is some online stuff I did today with a quick Google session

http://www.hammerzone.com/archives/elect/panel/sub_panel/01/overview.htm
http://www.howdididoit.com/AC/page5.html
http://answers.google.com/answers/threadview?id=702026

[V]

ok, that first link is very good, thanks
Its my parents house, and i'm planning on being in my own house by winter of '07 so I have about a year and a half left here. However, there is a possibility i may return here in 10-15 years(parents health/inheritance etc). So i will install a subpanel after all. Now the last thing i got to finalize is how i'm running the wire, then i can go and buy what i need. I got to see about running indoor or outside and underground... back to measuring, lol

[BonzoHansen]

Tell them it is an investment - it turns a 'detached garage' into a 'detached garge and workshop with updated electrical access'. Maybe they will swing/split the $$. :)

[Squirrel]

ill tell my bro to pop in here after work, he used to be an electrician

[paul100]

ok...so is this how to wire a subpanel...
install a 60amp breaker in my main box,
run 6/2 (w/baregound) wiring from that breaker to my garage,
mount a 4 space/8 circuit subpanel in garage,
connect 6/3 to new subpanel keeping neutral and ground isolated,
install double pole 30 amp breaker in new subpanel,
...then basically wire up my compressor as shown above using only 5' of 10/2 wiring...

Does all that sound close to correct at least?



I am not sure if you have a mistype when you say 6/2 but here is how I would do it. And no I am not an electrician but I work for a general contractor and I do alot of out electrical.
From the house you start with the double pole 60 amp breaker, You will run 6/3 with ground to the subpanel. In the main panel you connect the white and ground to the neutral/ground bus bar and the blk and red go to the 60 amp breaker. Run the new wire to a sub panel. Make sure it is a subpanel that has the neutral isolated from the ground. In the subpanel connect the red and blk to the main lugs and the white to the isolated neutral bar and the bare ground to the ground bar. Now any circuit you run from here on in this supanel must have the neutral and ground seperate. For your compressor I would run a 30amp double pole breaker and 10/3 or 10/2 which ever is needed) to a 30 amp 220v recepticle. Then hook up a cord that is rated for 30 amps to the compressor. Just make sure the plug on the cord matches the recepticle you used.