# options for 100amp sub panel in pole barn 250' away?



## Dennis Alwon (May 9, 2009)

Ron, What is the load on the house and what loads are being added to the pole barn. Without that info you are working in the dark. 

I also would use conduit because I have seen db cable go bad too many times.


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## HackWork (Oct 2, 2009)

This is a DIY question which we aren't supposed to answer.

I'm not sure of what today's cost difference is between pipe/XHHW and direct burial cable, but if you are doing the labor then you should definitely use the pipe.

Coming out of a 100A sub panel to feed another 100A sub panel may or may not be a problem. Depends on the load. Maybe run a 60A feed to the pole barn.


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## sbrn33 (Mar 15, 2007)

I would go with the mobile home cable if it was mine. I wouldn't worry much about voltage drop as the most you will ever use is 50 amps anyway. 24 inches deep and call it good. 
The URD is not rated to go inside the house but i believe the mobile home cable is.


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## Ron123 (Mar 19, 2016)

Thank you for the advice.


Although not a contractor, I am a state licensed electrician with plans of getting my Masters as soon as I can test. When I joined this site some years ago I asked the moderators if it was ok as I was an apprentice at the time. They obviously gave me the ok. 

FWIW, my brother will be pulling a permit for this job as even out in the country hard to build a pole barn without someone taking notice. 


As to the my original question I guess it just comes down to opinion.

Thanks,
Ron


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## Ron123 (Mar 19, 2016)

Maybe the mobile home cable is the way to go then if it can go in the house. That way he could run from 200 amp Main, along basement ceiling to other end of house, and then out.

Thanks,
Ron


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## HackWork (Oct 2, 2009)

Ron123 said:


> Maybe the mobile home cable is the way to go then if it can go in the house. That way he could run from 200 amp Main, along basement ceiling to other end of house, and then out.
> 
> Thanks,
> Ron


You can run it in pipe underground and then come up into a box in which you splice SE cable to go thru the basement of the house.

Have you looked at the prices? I'm not sure why you are so against pipe.


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## Ron123 (Mar 19, 2016)

Hack, if you read my OP its not me who's against pipe. This is for my brother, just trying to help him out. I told him to pipe it. I did my own in pipe along with a gas line too. It's about half the cost to direct bury. That's what he's looking at.

Thanks,
Ron


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## backstay (Feb 3, 2011)

I've only been doing this for 30 plus years, but pipe is cheaper than doing it again when it fails. Also as a contractor, I wouldn't run 2-2-2-4 to a 100 amp panel that far. Loads change and I don't need call backs to fix that problem. Here in MN, you couldn't run that size for a 100 amp feeder to anything but a dwelling. That has changed now, but I still only run that size to dwellings.


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## HackWork (Oct 2, 2009)

backstay said:


> I've only been doing this for 30 plus years, but pipe is cheaper than doing it again when it fails. Also as a contractor, I wouldn't run 2-2-2-4 to a 100 amp panel that far. Loads change and I don't need call backs to fix that problem. Here in MN, you couldn't run that size for a 100 amp feeder to anything but a dwelling.* That has changed now*, but I still only run that size to dwellings.


What change was made? I am on the 2014 but I looked at the 2017 and still see it showing #2 is good for 90A unless the provision for a dwelling is used.


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## backstay (Feb 3, 2011)

HackWork said:


> What change was made? I am on the 2014 but I looked at the 2017 and still see it showing #2 is good for 90A unless the provision for a dwelling is used.


Most state inspectors weren't passing #2 AL to anything fed with a 100 amp breaker unless it was a dwelling. Then the state said you could, some inspectors still said no. Then enough contractors complained and the state made the inspectors approve them. I still don't run #2 to those non dwellings. At 250 feet, the load would have to be under 50 amps.


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## Dennis Alwon (May 9, 2009)

backstay said:


> Most state inspectors weren't passing #2 AL to anything fed with a 100 amp breaker unless it was a dwelling. Then the state said you could, some inspectors still said no. Then enough contractors complained and the state made the inspectors approve them. I still don't run #2 to those non dwellings. At 250 feet, the load would have to be under 50 amps.


Why would the state allow #2 AL to be used at 100 amp. Just install a 90 amp overcurrent protective device. #2 cannot be used unless it is a dwelling service or feeder that carries the entire load of the dwelling


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## backstay (Feb 3, 2011)

Dennis Alwon said:


> Why would the state allow #2 AL to be used at 100 amp. Just install a 90 amp overcurrent protective device. #2 cannot be used unless it is a dwelling service or feeder that carries the entire load of the dwelling


I don't disagree, they are allowing detached garages to be fed with #2 and a 100 breaker. At least that's what I'm told. I don't do that, so I haven't checked into it. I just hear talk from other ECs and inspectors. Ever try to explain to a customer why there's a 90 amp breaker feeding their 100 amp panel? It's hard enough to get them past the "I need 240 because I'm going to put in a welder".


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## frenchelectrican (Mar 15, 2007)

To Op .,, 

I would run this in the pipe too. it maybe little cheaper to run in that distance and you can able upsize it later if need to without have to dig up the ground again.

I do use MHF ( mobile home feeder ) from time to time but ya have to be very carefull with them once you nick them it will become toast pretty fast.


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## sbrn33 (Mar 15, 2007)

Is the #2 carrying the whole load?


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## frenchelectrican (Mar 15, 2007)

sbrn33 said:


> Is the #2 carrying the whole load?


I supposed so but I dont know the excat details on the OP part but factor in the distance I would not bother run full 90 amp on that more like 60 or so. without getting serious voltage drop. 

But I did read the OP part the biggest load will be welder but who know what else will be on the same time.


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## Ron123 (Mar 19, 2016)

So what size wire should he go with? Using an online voltage drop calculator at 250' for 100 amp I'm coming up with 4/0 AL. That seems crazy to me. Even with a load calc at 50 amp it's saying 2/0 to 1 awg with vd ranging from 3-5%.

As I mentioned, barn will be storage. Doubt he will ever use a welder or anything similar as his 3 car garage is setup for that stuff already, and is never used. 

I will still be trying to convince him to go with pipe/wire. 

Ron


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## Ron123 (Mar 19, 2016)

Yes #2 will be carrying whole load


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## HackWork (Oct 2, 2009)

250' is far. See if the PoCo will run poles to the pole barn and put a separate meter on it. Maybe you'll get lucky, can't hurt to ask.


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## MechanicalDVR (Dec 29, 2007)

Ron123 said:


> So what size wire should he go with? Using an online voltage drop calculator at 250' for 100 amp I'm coming up with 4/0 AL. That seems crazy to me. Even with a load calc at 50 amp it's saying 2/0 to 1 awg with vd ranging from 3-5%.
> 
> As I mentioned, barn will be storage. Doubt he will ever use a welder or anything similar as his 3 car garage is setup for that stuff already, and is never used.
> 
> ...


That voltage drop is why guys are saying no more than 50 amps on the #2. 

PVC pipe is cheap, convince him to go with pipe and a 60amp panel.
The pipe in place will be an asset down the line.


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## backstay (Feb 3, 2011)

50 amps, #1


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## HackWork (Oct 2, 2009)

There was a time that cable cost more than pipe and separate conductors because it was much easier to install. But then the cable prices came down. I haven't looked at the difference in price in a long time, but I can't imagine it being much different. 

The labor will be more with pipe and separate conductors, but it's still easy as hell and they aren't paying for labor so it shouldn't matter.


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## Ron123 (Mar 19, 2016)

So that VD calculation refers to the feeders to the barn. How does that affect a 120v branch circuit coming from the barn subpanel?

Thanks,
Ron


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## flyboy (Jun 13, 2011)

HackWork said:


> There was a time that cable cost more than pipe and separate conductors because it was much easier to install. But then the cable prices came down. I haven't looked at the difference in price in a long time, but I can't imagine it being much different.
> 
> *The labor will be more with pipe and separate conductors, but it's still easy as hell and they aren't paying for labor so it shyouldn't matter.*


Unless they changed it, most inspectors want to see direct burial on a 6 in.bed of sand and then covered with sand before back filling. What a pain in the azz compared to just installing it in pipe.


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## frenchelectrican (Mar 15, 2007)

Ron123 said:


> So that VD calculation refers to the feeders to the barn. How does that affect a 120v branch circuit coming from the barn subpanel?
> 
> Thanks,
> Ron


Just a very small number change but it depending on the conductor size and distance that will change the number of the voltage drop and most 120 volts branch circuits typically are #12 and the max distance is typically about 100 or so feet to keep the voltage drop to minuim


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## Ron123 (Mar 19, 2016)

Ok just want to say thanks for all the input I really do appreciate it!

Ron


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## RePhase277 (Feb 5, 2008)

I can tell you now, you don't want VD:no:


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## Ron123 (Mar 19, 2016)

RePhase277 said:


> I can tell you now, you don't want VD:no:



Sounds like experience talkin'


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## sbrn33 (Mar 15, 2007)

flyboy said:


> Unless they changed it, most inspectors want to see direct burial on a 6 in.bed of sand and then covered with sand before back filling. What a pain in the azz compared to just installing it in pipe.


I have never heard of that ever. I would love for you to give me the code section?? Is it a good idea yep, probably but code **** no.


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## sbrn33 (Mar 15, 2007)

Ron, don't listen to these guys, run the underground wire and be done with it before they even have the pipe glued together. Much less struggle to get a line thru.
This is a resi situation and money is a factor. If it does ever get hit the direct burial is way easier to repair.


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## splatz (May 23, 2015)

to the OP, you keep saying you're not concerned about voltage drop because isn't the welder fairly sensitive to voltage drop, as in it will not weld as well with over 5% or so voltage drop? What's the actual draw of the welder? If it's really just the welder and some LED lights and a few receptacles, the load could be pretty small. 

The pipe is the way to go, friends don't let friends bury wires.


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## Ron123 (Mar 19, 2016)

splatz said:


> to the OP, you keep saying you're not concerned about voltage drop


I don't think I said this...


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## telsa (May 22, 2015)

Ron123 said:


> I don't think I said this...


Tip of the day: LOAD GROWTH.

I don't care what 'they' say -- in the not too distant future -- they'll change their minds.

They'll keep adding loads -- over and over.

THAT'S why pipe -- and over-sized at that ( 2" ? ) -- is THE way to go.

They are providing the labor, are they not ? PVC is a SNAP to lay down. 

An over-sized PVC run is a delight to pull conductors into.

They're providing the labor for that, too.

They can pull cheap alumunim today -- and jump to copper down the road when their wallet can afford it and the need is compelling.

A pole barn eventually demands a work shed... for this and that.

Next thing you know, compressor, welder, ... etc.


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## HackWork (Oct 2, 2009)

I subscribe to the idea that if you install a 100A panel, it better be able to handle 100A. 

If you only want to run cable large enough to handle 50A with voltage drop in spec, then put it on a 50A breaker and call it a 50A panel.


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