OT - wire size

Beanmedic

Member
My tractor shed (open sided metal roof) is in need of electric power so I can put in a light or two and a few outlets. It will require I bury about 100 feet of conduit/wire and another 40 feet or so above ground going through my barn to the panel. I'll put a small breaker panel, or at least a fused master cut off switch at the tractor shed to make servicing that end easier/safer.

I don't [i:86c3ab0e26]think[/i:86c3ab0e26] I'll ever need 220 volt at the shed. From what I can read it looks like I need #10 THHN to run a 120 volt circuit that would provide 15-20 amps for a few lights and a couple of outlets (battery charger, work light, etc).

Does this sound correct?
 
I have nothing to add, just that I thought the topic said "wife size". I was preparing to see what this can of worms would look like.

Wait, I do have something to add. Put in twice as many outlets as you think you need. There are never enough orange extension cords and they are a pain to step over.

You are on your own if you want to talk about the size of your wife!
 
Depending on your age and mechanical requirements, I would like to recommend that you consider your needs over the next twenty years.

Run larger wire, perhaps #6 for a 50 amp capacity to your shed. 220 volts, single phase.

Once done, you will have a long range idea for personal collection growth in equipment and mechanical capabilities.

Maybe air compressor, 15 amps. 220 volt.
Electric welder for repairs and general maintenance and construction jobs. 40 Amps, 220 volts.

More lights and outlets. No need for battery operated stuff. Hand tools. Shed Work.


110 v. battery charger. electrolysis work.

The list can go on, however, I am sure you get the idea.

John,PA 40 year veteran of collections.

Battery charger.
 
(quoted from post at 11:58:36 02/07/14) Depending on your age and mechanical requirements, I would like to recommend that you consider your needs over the next twenty years.

Run larger wire, perhaps #6 for a 50 amp capacity to your shed. 220 volts, single phase.

Once done, you will have a long range idea for personal collection growth in equipment and mechanical capabilities.

Maybe air compressor, 15 amps. 220 volt.
Electric welder for repairs and general maintenance and construction jobs. 40 Amps, 220 volts.

More lights and outlets. No need for battery operated stuff. Hand tools. Shed Work.


110 v. battery charger. electrolysis work.

The list can go on, however, I am sure you get the idea.

John,PA 40 year veteran of collections.

Battery charger.

I totally agree, go with 220. You will be glad you did.
 
I agree with 240V service & I have a 100 amp service in the
barn, and use it - stick welder and a few other things at the
same time will take more than 50. As others say - plenty of
outlets including a few 240s that I use for the air compressor
and shaper. You can never have enough.
 
My shop is old and runs off a 15amp circuit from the house. I cannot tell you how frustrating and limiting that is to my ability to work in there.

If you're going to the trouble of burying cable, make the investment in 220 volt. I think you'll be happier in the long run.

Colin, MN
 
David I'm a bit scared, but I'm with John here.
It would be easier to pay the little extra to put in 220 now
than to dig it back up and do it a second time.
I never [i:b3b215040e]thought[/i:b3b215040e] I'd need high speed internet in my shop
either, but times have changed and I use it regularly now.
I lucked out. Because I had buried everything in large diameter
conduit I had enough room to fish the Cat 5 cable through.

Check the prices, cable designed to be directly buried may be
cheaper. It was the last time I bought it. I put it in conduit anyway.
 
I have 220 volt at my barn, where compressor and other shop equipment is. I also have a three phase converter there I made from a delta wound motor and some three phase equipment. Can certainly do 220 volt single phase to the tractor shed...it's only one more wire. Probably is a good idea. But, the #8 does get a little pricey. What would be my capacity limits using #10 given the distances I cited?
 
John sounds right to me. I ran a similar setup to my shed. 60 Amp breaker in the house to a disconnect and then a subpanel, both in the shed. I ran 12/2 wire for 20 AMP at the 20 AMP outlets. You can use 14/2 for the lights. Don't forget to put a GFCI at the start of every circuit you run. Check code for your area you will probably need a ground for the shed. Two eight foot ground rods from a continuous ground wire from the subpanel. If you run 2 hots a neutral and a ground you will have 220 volts if you ever need it. It would be a good idea to put it in conduit to the shed. I also put in a few outside outlets for outside work, also on a GFCI.
 
Forgot to add. It's kind of like Shed Math. Figure how much space you need, double it and you'll still wish for more later. If you go to all the trouble of wiring the shed and don't plan for expansion, I guarantee a year from now you will be kicking yourself. It's a lot harder to add on after you have buried everything.
 
I would suggest running the extra wire for 220 and then using one
side for lights and the other side for outlets. If you overload or
trip a breaker using a tool at least you are not left in the dark and
you can see you way back to the breaker panel.
 
I"ve seen & been involved in discussions like this in my yrs as a contractor . Some people ask but refuse to accept my advice , then yrs down the road I see them having it upgraded by someone else (probably roo proud to ask me) . The distance you are talking about will definitely cause you issues of voltage drop . My advice professionally is to do it right now so that in a couple yrs , you aren"t kicked butt because you didn"t accept experienced advice . I would run no smaller than (3)#6 wires out to your shed & then add an 8" grd rod with auxillry grd from it to the grd bar in your panel .The #6 wires will be (2) hots & (1) neutral connected to a 50 amp double pole main breaker . Then use a 20 amp single pole breaker for the receptacles (which should be grd fault recepts). Then use a 15 amp single pole breaker for the lights . Now the code calls for any receptacle used outside or in an exterior building should be a GFI type receptacle for safety .The extra grd (buried 8" grd rod)is also code & safety . You will not regret the extra expense for materials & time . God bless, Ken
 
David,
If you bury the conduit then you would need THWN wire, the W is for wet (underground) use. Some wire is marked THHN/THWN if I recall correctly, that's fine too. I would run an inch or inch and a quarter conduit, pull in 10 gauge conductors, don't forget a ground, and add mule tape. Then if you decide to add later you can use the mule tape to pull in some 6 gauge, or even a separate 12 gauge just for lights, and make the receptacles a separate circuit. I'd use LED lamps, they use lots less power! The larger size conduit will be there in twenty years if you want to add fiber optics or a big flux capacitor charging system. This is an open sided shed, I think your original plan would serve you we'll for now, and bigger conduit isn't much more expensive for 150 foot run. I'd put in a small sub panel now, with cgi breakers for what you're going to use now, and that would still allow you to bump up later if you need to.
Good luck with your project.
Jerry
 
Wow...a lot of good advise!

To make sure I understand the ground, one or two 8 foot ground rods at the shed, wired (unbroken) back to the panel at the barn? And, is the ground typically the same gauge as the hot and neutral wires? Can you use naked copper for the ground? I think I have that on hand, although it is solid and may be impossible to pull.
 
Like you I am working on power to an out building.
I have a AC/DC welder, plan on a not huge compressor at this time and a outlet pretty much ever 6ft for ease pf use.
I was going to use 8ga in conduit underground. After talking with a maintanence guy from work I am biting the bullet and running 6ga. The differance is cost is about $60 for me for the 125 ft from main box to new subpanel. Also going with grounding rods near building as well as at main panel.
Basiclly everything these guys have said.
 
If I were you I would ask questions like this on Tractor Talk or better yet Tool Talk.
I would guess that only about 15% of the YT users even read the N board where as on Tractor Talk probably 70% of the YT veterans read that board.
Electrical gurus like Dr Sportster, John T, Buick & Deere and Mike WA frequent those other boards and are very good about answering questions like this.
FWIW, I wanted to put electric heat in my deer hunting blind last fall so I trenched in a 3/4" pvc conduit line and ran two strands of #10 THHN to it. About 225'
I got about 10% voltage drop but the electric heater (and coffee pot) in it work great.

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100_1442.jpg
 
i'd wire it for 220 just because.

extra capacity.

air compressor.

welder.. etc.. etc...

if it ever becomes a bigge rbuilding.. stub power there. AC heater.. etc..e tc..
 
Check a website that tells you the voltage drop using a given size of wire, drawing a given current over a given distance. I think you will find that you need to use larger wire than #10, or even #6, or else you will have excessive voltage drop if you draw any substantial current over a 100-foot run. I used 2-gauge for a 100-foot run to my barn.

The ground line should preferably be a separate wire from your main panel ground to the barn's subpanel ground. If you don't want to run a separate ground wire, then you can use a ground rod at your barn for the ground wire, but this is not nearly as good a ground as one coming from your main panel and will create an undesirable potential difference between the two grounds.

If you run only a 110 circuit, you will likely unbalance the two 110-volt legs of your 220 service going to the main panel, so you'll have lower line voltage on one 110-volt leg in your house than on the other 110-volt leg. It is much better to keep the current draw on both 110-volt legs roughly equal, and you can only do this by running a 220 line and then dividing the 110-volt legs into roughly equal loads when you wire the barn.

Remember that while you only need to run 3 wires (including ground) for a 110 circuit, you need to run 4 wires (2 for the 110 leg hot wires, one for neutral and one for ground) for a 220 run. The latter (4 wires, 220 run, included ground) is the way a good electrician would wire it.
 
"The latter (4 wires, 220 run, included ground)"
Would not meet code here without the additional ground rods.
Separate ground at/near the sub-panel is required.
Might be different in your area, just going by what was required here.
 
(quoted from post at 23:21:21 02/07/14) "The latter (4 wires, 220 run, included ground)"
Would not meet code here without the additional ground rods.
Separate ground at/near the sub-panel is required.
Might be different in your area, just going by what was required here.

FWIW I don't believe it meets the NEC either.

TOH
 
I have ground rods on hand...so pounding those in won't be a problem.

TOH...sent you an email, but have had some issues with mine lately. Did you get it? About a hydraulic top link.
 

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