Running electric to a barn


  #1  
Old 06-15-18, 06:21 AM
S
Member
Thread Starter
Join Date: Jun 2018
Posts: 5
Upvotes: 0
Received 0 Upvotes on 0 Posts
Running electric to a barn

Hello, I’m looking to run power underground to a barn. I need to know the best wire to use and what route to take. It’s a 200amp main service coming to the house, from the house I’d like to add a 60 amp two-pole breaker to power a sub panel in the barn that will be used for lighting and some power tools. The distance from the barn to the main panel is right around 200’. The main panel is on the exterior of the house, but the wire will need to run into the basement/crawlspace (more of a cellar really, not livable or used space) to get to the panel as that is the most direct route. What wire would be acceptable for this use, and is there a problem with running the wire into the house?
 
  #2  
Old 06-15-18, 06:26 PM
Geochurchi's Avatar
Member
Join Date: Nov 2012
Posts: 5,073
Received 161 Upvotes on 147 Posts
Hi,so if this run will be entirely above ground ?
Geo
 
  #3  
Old 06-16-18, 05:10 AM
S
Member
Thread Starter
Join Date: Jun 2018
Posts: 5
Upvotes: 0
Received 0 Upvotes on 0 Posts
No, it will be run below ground from main panel to barn.
 
  #4  
Old 06-16-18, 06:03 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 14,319
Received 874 Upvotes on 737 Posts
Inside the house I would suggest running a cable unless it is easy (fairly straight) to run a conduit. Then where it exits the house install a box and convert it to PVC conduit and run thhn/thwn conductors underground to the barn. Your other option would be to run UF the entire way (direct burial) but the cable would still be required to be protected when not in a wall (studs or joists) or 24" underground.

I just remember that you may only have no more then 360 degrees worth of bends in the conduit run, The conduit must be installed completely before pulling in the wire, and must be buried minimum of 18" down.

At 200' you may also have voltage drop issues depending your expected load. Many people mistakenly calculate voltage drop by the full rating of the breaker or the sub panel. This is not correct as very rarely is a feeder used to full capacity. If you are really only going to use some lights and light power tools you would likely be just fine with #6 copper wires. However if you think this could turn I to something more then you should consider upsizing the wire to compensate for voltage drop.

I have a horse barn at my house about 220' away and I ran #8 thhn in conduit connected to a 50amp breaker. The barn has lights, a shallow well, and some heaters to keep the water from freezing. I have never had an issue with voltage drop. Just some food for thought.
 
  #5  
Old 06-16-18, 08:19 AM
S
Member
Thread Starter
Join Date: Jun 2018
Posts: 5
Upvotes: 0
Received 0 Upvotes on 0 Posts
Would an aluminum 2-2-2-4 mhf feeder be sufficient? I know it will have to be in conduit inside the house.

I plan on running pvc conduit the entire run underground.
 
  #6  
Old 06-16-18, 08:46 AM
Geochurchi's Avatar
Member
Join Date: Nov 2012
Posts: 5,073
Received 161 Upvotes on 147 Posts
I would run individual conductors, if you are using PVC, that 2 2 2 4 is way over sized # 4 THWN/THHN would be plenty IMO.
Geo
 
  #7  
Old 06-16-18, 09:02 AM
S
Member
Thread Starter
Join Date: Jun 2018
Posts: 5
Upvotes: 0
Received 0 Upvotes on 0 Posts
#4 is almost $1 per foot and I need 4 conductors that’s $4 a foot. He mhf is only $1.43 per foot. Copper is too expensive for the length I’m running
 
  #8  
Old 06-16-18, 09:17 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 29,711
Upvotes: 0
Received 15 Upvotes on 13 Posts
You could use aluminum XHHW #3 0r #2 for three of the wires and #6 aluminum for ground. (Upsized based on 200 foot run.)
 
  #9  
Old 06-16-18, 09:49 AM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,515
Upvotes: 0
Received 276 Upvotes on 252 Posts
What is the point of installing a subpanel feed with 60 amp breaker expecting that the full 60 amps will be only rarely needed and that significant voltage drop will be suffered near or at the full 60 amps?

When the full 60 amps is drawn, chances are that it will be for just a short period of time but the draw will be in connection with something that is very sensitive to voltage drop such as a motor starting up.

IMHO no, you would not base the feed capacity (in terms of wire gauge) on the sum of the ratings of the breakers in the subpanel but yes you should select the wire gauge to provide the full number of amperes which the circuit is described as providing and probably protected for not subject to brownout conditions voltage drop..

No. 4 copper or #3 aluminum would be right for 60 amps here.
 

Last edited by AllanJ; 06-16-18 at 10:49 AM.
  #10  
Old 06-16-18, 11:05 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 14,319
Received 874 Upvotes on 737 Posts
[What is the point of installing a subpanel feed with 60 amp breaker expecting that the full 60 amps will be only rarely needed
For the same reason you install a 200amp service in a house never expecting to get even close to the 200 amps. If you expect to get close to the maximum capacity of the panel you should be installing a larger panel/feeder.

I have only seen a few items that are affected by voltage drop, and that drop was greater then 20%. Most of them have been UPS backups or very sensitive electronics.

All that said, I would agree with running large wire is a good idea. 2-2-2-4 is fine as it might be more readily available at the home store. You could then upsize that breaker if you choose. You are really limited by the materials you can get locally.
 
  #11  
Old 06-16-18, 02:46 PM
S
Member
Thread Starter
Join Date: Jun 2018
Posts: 5
Upvotes: 0
Received 0 Upvotes on 0 Posts
I appreciate all the help. Would a 2-2-4-6 work for this application? It’s easier to get and cheaper (but I can still get 2-2-2-4 no problem). And I’m thinking 2” conduit?
 
  #12  
Old 06-16-18, 03:59 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 29,711
Upvotes: 0
Received 15 Upvotes on 13 Posts
Would a 2-2-4-6 work for this application?
It should but it depends on the 120v loads.
 
  #13  
Old 06-16-18, 07:06 PM
Geochurchi's Avatar
Member
Join Date: Nov 2012
Posts: 5,073
Received 161 Upvotes on 147 Posts
You may want to check prices at an electrical supply house if there one near you, prices are MUCH higher in the big box stores, at least around here.
Geo
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: