Running electricity to outside shed?

[edge-of-the-woods]

Hi all,

So I have run my share of wire in new houses and outside before, but always for audio systems. This is my first time running power out to a location outside, but I am not a stranger to conduit, pulling wire, etc.

We need to keep the water for our chickens from freezing over the winter, and I am going to use a pipe heater cable to do that ( http://www.homedepot.com/p/Frost-King-6-ft-Electric-Water-Pipe-Heat-Cable-HC6A/202262328 ).

Problem is getting power out to the coop, it's about 150' away from the house. I can easily get wires outside, and run them through 1" metal conduit out to the coop, then set up an outdoor outlet on the outside of the run.

No idea what gauge wire to use, though. Any recommendations? I know I can't just pull romex through, it has to be black/white/ground pulled together.

Thanks!

 

[Highbeam]

I've done this a few times. Use a 20 amp 120 volt circuit breaker to feed 12 gauge THHN/THWN. You can upsize this if you want to 10 gauge but I wouldn't. I am not afraid of voltage drop on a residential circuit. Your heat tape won't care. Be sure that your spool of wire is long enough to make it without a splice.

Lay the conduit (I use plastic) and then vacuum a pull string through and then pull the wires through all at once. I would go inside the shed with the circuit and then mount an outlet to the outside fed from the inside. GFCI of course.

We have two chicken water tanks. In freezing weather I alternate them so that one is thawed. Birds don't like to drink ice. Also, I put a light in the coop on a timer to simulate the sun rising which keeps them laying during our short days at this latitude. The birds like that but don't worry about them getting cold. They are surprisingly good at dealing with cold.

 

[edge-of-the-woods]

That is awesome! Thanks!

Now I just need to find the best spot to take the wires from the basement to the outside....

 

[semipro]

Cable lube can be very helpful.
http://www.homedepot.com/p/Klein-Tools-32-oz-Premium-Synthetic-Clear-Lubricant-51028/100660159

 

[begreen]

Is this for underground? For a coop I would just bury UF cable and not bother with the conduit except where it leaves the house and where it enters the coop. UF (underground feeder) is like romex in an extra tough jacket. I'd use 12/2 UF cable.
http://www.homedepot.com/p/Southwire-250-ft-12-2-Gray-Solid-UF-B-W-G-Cable-13055955/202316281

 

[EatenByLimestone]

If its only for a single heating strip, which will be drawing just over the consumption of a 40w light bulb, I'd be hard pressed to not lay an extension cord for the winter. If you wanted to install mood lighting for the chickens, you may need to upgrade, but maybe not if you choose LED.

 

[iamlucky13]

That's long enough that if you want to stay within the recommended 3% voltage drop at maximum current, you'd should use 10 AWG for a 20A circuit, but I don't think that is actually code required, just preferred. I bring it up in case you might want to use power tools or space heaters out there on more than rare occasions. The downsides are 10 AWG costs twice as much as 12 AWG, and is harder to pull through conduit and fit inside your junction box.

Additional things to keep in mind:
- Underground Feeder wire can be direct buried (no conduit), but must be at least 24" deep. Where it comes out of the ground, you need to protect it in conduit down to 24".
- Plastic conduit must be buried at least 18" deep, except since you're going to be less than 20A and 120V, you're allowed to go only 12" deep.
- Metallic (generally RMC or IMT, but I think EMT is technically allowed) is more resilient to digging tools, so it only needs to be buried 6". It will eventually corrode.

I prefer never to have to worry about hitting a cable, so even if I were going to use metallic, I'd go 18", but since PVC is much cheaper, not exactly weak either, and never corrodes, that would be my method of choice.

Lastly, I've heard a lot of debate on this, but my understanding is that NM cable (aka "Romex") is not allowed underground, even in conduits, because you have to assume the conduit won't keep water out forever, and the sheathing is not rated for immersion. I know that countless people run NM-B cable underground in conduit and never have a problem, but I think you're supposed to use UF-B regardless of whether you go direct burial or conduit.

 

[fbelec]

- Plastic conduit must be buried at least 18" deep, except since you're going to be less than 20A and 120V, you're allowed to go only 12" deep.

nope 24 inches regardless

- Plastic conduit must be buried at least 18" deep, except since you're going to be less than 20A and 120V, you're allowed to go only 12" deep

never heard of anything down only 12 inches not even phone or cable

- Metallic (generally RMC or IMT, but I think EMT is technically allowed) is more resilient to digging tools, so it only needs to be buried 6". It will eventually corrode.

emt not allowed at all

Lastly, I've heard a lot of debate on this, but my understanding is that NM cable (aka "Romex") is not allowed underground, even in conduits, because you have to assume the conduit won't keep water out forever, and the sheathing is not rated for immersion. I know that countless people run NM-B cable underground in conduit and never have a problem, but I think you're supposed to use UF-B regardless of whether you go direct burial or conduit.

agreed. it is against code and every time i go in for code update class someone asks why and tells everyone there how he never had any problem with doing it that way. (that's probably because he never got called back) i've been in to fix it.

 

[iamlucky13]

Plastic conduit must be buried at least 18" deep, except since you're going to be less than 20A and 120V, you're allowed to go only 12" deep.

nope 24 inches regardless

I'm not an electrician, but when I prepped the path for the feeder line to my garage, I was given the same guidance as NEC table 300.5. Both the electrician who hooked it up and the inspector ok'd 18 inches:
http://www.xwalk.com/images/Table_300.5-Min_Cover_Reqts.pdf

I'm not clear on the question of using EMT underground. I did a search before I posted and generally trustworthy forums like Mike Holt and InterNACHI seemed to indicate it was technically allowed by the code, but no self-respecting electrician would do it.

At best, I guess the OP should be aware that EMT is the thinnest of the metallic electrical conduit types and would corrode away the fastest.

 

[fbelec]

I'm not an electrician, but when I prepped the path for the feeder line to my garage, I was given the same guidance as NEC table 300.5. Both the electrician who hooked it up and the inspector ok'd 18 inches:
http://www.xwalk.com/images/Table_300.5-Min_Cover_Reqts.pdf

I'm not clear on the question of using EMT underground. I did a search before I posted and generally trustworthy forums like Mike Holt and InterNACHI seemed to indicate it was technically allowed by the code, but no self-respecting electrician would do it.

At best, I guess the OP should be aware that EMT is the thinnest of the metallic electrical conduit types and would corrode away the fastest.

your inspector is a easy going guy. not to say the inspectors here are hot headed but if i tried 12 inches to a shed or garage i would get the smile and a nope go deeper.
now if you take the time and extra materials (concrete) for 18 inches or 12 even with the extra time digging it's cheaper to go the 2 feet and be done with it. but the guys around here just won't take anything less than 2 feet. same with cable and phone. emt underground they would look at me like i got three heads before (you know better than that talk) around here it would rot out in under ten years. most inspector can be a pain sometimes but they are mostly looking out for the home owner and doesn't want the home owner to get a bad job.

 

[edge-of-the-woods]

Wow. Wow. I hoped you folks would be as knowledgeable as this as you are about wood, and it seems that way!

So, taking all of this together....if I just wanted a quick fix for this winter, could I combine the "just an extension cord" idea and the "UF cable", and make a giant extension cord out of the UF? Meaning that I would 1) not bury it and 2) not tie it into a breaker, but build a plug at the end inside the house, and just plug it into a normal outlet?

That would save me a tremendous amount of time and effort, which would be nice because we're expecting a baby in February, and my To-Do list is pretty hefty. Then I could bury it properly in the spring/summer of next year, and tie it into the panel inside the house.

Thanks

 

[semipro]

So, taking all of this together....if I just wanted a quick fix for this winter, could I combine the "just an extension cord" idea and the "UF cable", and make a giant extension cord out of the UF? Meaning that I would 1) not bury it and 2) not tie it into a breaker, but build a plug at the end inside the house, and just plug it into a normal outlet?

That would save me a tremendous amount of time and effort, which would be nice because we're expecting a baby in February, and my To-Do list is pretty hefty. Then I could bury it properly in the spring/summer of next year, and tie it into the panel inside the house.

Thanks

I'd consider doing that - with a caveat.
I'd want any circuit feeding an outside device on what amounts to an extension cord to have GFCI protection. You could use an exterior rated GFCI outlet or a GFCI extension cord.
I"m not sure UF is necessarily UV resistant so I'd probably look for cable with that characteristic. Sometimes "it will only be out there for one season" turns into years.

 

[iamlucky13]

your inspector is a easy going guy. not to say the inspectors here are hot headed but if i tried 12 inches to a shed or garage i would get the smile and a nope go deeper.

It's not about being easy-going, but about what he has authority to enforce. In my area, that's the NEC, with a few specific additions.

In your area, that could very well include different bury depths related to your local conditions, especially since I'm sure frozen ground is a more significant issue in your area than mine.

Good, friendly advice is one thing. Creating requirements that aren't in the code is another, although sometimes it's easier to just comply, especially if only following the code minimum actually is a bad idea for a given circumstance.

 

[NateB]

And if your are going to do all that digging, you might want to put some water out there also. Congrats on the baby. The first or one of many?

 

[fbelec]

Just don't put the water inthe same trench. I'm not trying to make a pissing match out of this and this is my bread and butter so this is my experience dealing with inspector's. Now since you have access to a code book there is a code that states that the jurisdiction has the right to change the code to fit his jurisdiction

That's all folks I've been told
Good night

 

[edge-of-the-woods]

This is the wire I am looking at:
http://www.homedepot.com/p/Cerrowir...led-Stranded-THHN-Cable-112-361253C/205493357

It's stranded, jacketed, but the three aren't sheathed together.

I could run this in conduit above-ground for over the winter, then bury it come spring.

 

[iamlucky13]

THHN is the non-wet rated insulation. If you go with a non-sheathed wire, it should be THWN for use in a conduit. Also, that's only 100' roll, and you said your distance is 150'.

Since this wire won't be handled much, there's also not much value to stranded wire over solid. It does pull easier, but you only deal with that once. You can get 250' of 12-2 UF-B for less than $100.

Make sure you leave yourself enough extra in your temporary hook up so you don't end up short when you move everything around to bury it.

 

[edge-of-the-woods]

From what I can see, THHN and THWN are often the same product. This THHN, for example, is listed as suitable for wet locations.

http://www.homedepot.com/p/Southwire-100-ft-12-Black-Stranded-THHN-Wire-22964152/204868213

I could run 4 of those...white, green, red, black. That way I can have an outlet and a switched light at the far end where the shed is located. I'm thinking of running it though sealed conduit now, and burying it in the spring.

 

[Sberry]

Its not legal on top of the ground, there is an exception for 12 inch burial if it is gfci before it leaves the first building and no nmb and no emt.

 

[sportbikerider78]

I just went through this, except, I went much farther...500'. I used 12/3 wire which has 4 wires in it. Red, brown, white and unsheathed ground. Bought it at home depot for $117 for 250'. I went with the 3 wire so that I could have 2 circuits that share the ground. Very handy.

It all sounds well and dandy to bury "no less than 24" or no less than 18", but what happens when you hit a mammoth boulder or a root bundle that you can't go through and can't go around? I had this happen about 4 times over 500". I have hard clay soil and tons of roots and big rocks on my property and there is no way around it.
In the areas were there is heavy traffic (like under my driveway) I put it 18" down and used PVC.

Many times I had to zig and zag to keep depth and many times I could not do that. I'm so glad I didn't use conduit because then it would have double or tripled the amount of time it would have taken to drop the wire in. Wire goes on top of the roots around the big rocks easily.

I was using a 1000lb trencher and it almost tore me in half a few times. If you hit a root at full bore it will jerk down and drop the handles 2' in about 1 millisecond.

 

[Highbeam]

I was using a 1000lb trencher and it almost tore me in half a few times. If you hit a root at full bore it will jerk down and drop the handles 2' in about 1 millisecond.

I've trenched many hundreds of feet, maybe thousands, using one of these things for pipe and wire. Basically a big chainsaw for the dirt. My favorite is when the rocks get in between the chain and the bar and jam it. Or when you throw the chain due to rocks. Lot's of bruises on the hips from the handlebars slamming into your sides. Then you get to go back in with a clam shovel (those skinny shovels) to clean out the trench.

Rocks are all the more reason to use conduit. I hate to think about the wire laying against a rock that is moving around due to frost heave or a root that continues to move and grow.

 

[sportbikerider78]

I don't disagree that it is ideal. But sometimes a 300lb rock buried 15" down has other plans.

 

[Sberry]

THHN is the non-wet rated insulation. If you go with a non-sheathed wire, it should be THWN for use in a conduit. Also, that's only 100' roll, and you said your distance is 150'.

Since this wire won't be handled much, there's also not much value to stranded wire over solid. It does pull easier, but you only deal with that once. You can get 250' of 12-2 UF-B for less than $100.

Make sure you leave yourself enough extra in your temporary hook up so you don't end up short when you move everything around to bury it.

Right, buy a 250 ft roll. Many a pole barn has been built from 150 ft of cord. You can run tools from that, some voltage drop in this is irrelevant.
To a shed would direct bury if I could and gfci before it left the house, if any of the building is really going to be wired it needs a simple switch as a disconnect which kills power to the whole structure.

 

[edge-of-the-woods]

Got this done, and kept it to code. Thanks for everyone's help!