Installing Electric To The Barn

[Hoeman00]

I ran 200 amp to the house and 200 amp to barn.
In the shop my Lincoln welder will trip a 60 amp
breaker after welding for a while (I replace breaker
after it starts tripping frequently).
Air comp takes 25+ amps and sometimes run both
at same time.
Also didn't like running thru house box (200 amp and
100 amp circuit to shop) and lights dim when working.

 

[Makers_Mark]

<font color=blue>What type of wire is needed for an underground 200 amp feed in plastic conduit (say 400')? </font color=blue>

I have the same question. I'll need to run 100-200 amp service into my workshop for welders, plasma cutter, compressor, etc. I already have seperate service for my barns. I'm thinking of upgrading that to 200, then breaking off to another 100 amp box. Does this sound do-able? It sounds smarter to run the wire through conduit rather than drop it straight in the ground.

 

[Anonymous Poster]

I would run 4/0 copper with a 2/0 ground. Min. 1in. conduit. (4 #4s max)

 

[Anonymous Poster]

Any wire buried directly in the ground has to be rated for such use. Also 200A in aluminum would have to be sized either 250 or 300mcm depending on the type. Aluminum isn't as good a conductor as copper, thus the upsizing.

 

[Anonymous Poster]

Off a 200 amp service, you can run up to two 100A sub panels. Direct burial or conduit is ok. I used conduit just so I could run future wiring thru it as needed. Sub panels must have a disconnecting means.

 

[beenthere]

WOW!! That question sure got a lot of response, and very good information. But the project just got a whole lot more expensive. /w3tcompact/icons/frown.gif

I would only add that when I did the same thing (electric to shed), I also added a 12-3 cable so I could switch power on or off from the house. That way I could plug in the block heater and turn it on from the house, usually an hour or two before I wanted to head out to start the tractor. I also have a yard light at the shed that I can turn on/off from either the house or the shed.

Trev. I think the contractor who buried your wire 6' under was also thinking more of his pocket than any need to bury wire that deep. IMHO, it isn't necessary at all. Water pipes maybe, but not electric. Unless he thought you were going to get rambunctious with your 4300, and start digging some real deep holes. I am not sure if the diggers hotline could even locate your wires that deep in the ground. But for most reasons, they wouldn't have to.

 

[boustany]

My 2 cents (I done it it) is bury the fattest 3 conductor cable you can afford (Of course 3 conductor means red, white, black, and ground). You may figure you'll save money with 12/3 or 10/3, but the amound of effort and expense running the wire will be more than that. If you put in a 12/3 you'll be saying "why didn't I bury a 4/3" for the next 20 years.

Basically, set up a sub-panel, even a really small one. So you'll have a 60 amp subpanel in the barn with 4 or 8 circuits. This panel will be fed off a 60 amp breaker in your main box. I think most codes require you to keep ground (copper) and neutral (white) separate in sub panels.

In any event, find out what local codes are, and check before you dig. Its a good idea to run the cable through a pipe or simething, but cheap corrugated drain pipe will do ok. I ran the 'phone while beside the pipe and had no problems.

Of course, if you don't already have a backhoe, this can be a great excuse to use on your spouse to buy one...

 

[RobS]

If you do go with aluminum I'd have an electician handle it for sure. There are some special coatings etc. to handle the dissimilar metal corrosion with the copper. The house I grew up in was built with aluminum wire throughout and almost burned down several times /w3tcompact/icons/shocked.gif

 

[kcbarnes]

You have good info so far, but one thing I have done is run a 1 1/4 to 1 1/2 pvc all the way and only run #10 for a couple of circuts for my needs now and then I could always pull out the small wires and install a 60 or 100 amp service later with no digging. Run a 3/4 pvc for the phone.

 

[jmattox1]

I am glad you caught that on the 10awg, RayS. If someone else wouldn't have said somethin I would have.

 

[Anonymous Poster]

There are 2 problems with aluminum.
#1 being dissimilar metals, they cause galvanic action between the copper and aluminum. You can stop that by using something called NOALOX by Ideal corp. It's available anywhere electrical supplies are sold.
#2 is that the metals heat and cool at different rates. This causes problems in the connections. Over time they will loosen up and start sparking. This is the biggest problem in older houses with aluminum.

 

[Hoeman00]

If running conduit need to go bigger than 1.5" for
future use.
U can only fill 50% of conduit .
The cost will be more than running 100 amp.
aluminum and use plenty of de-ox on clamps.
My old barn was a dairy 25 years ago and had
aluminum wire feeding it, was working till I moved
everything to new polebarn.
The old problem w/ aluminum wire was devices
weren't rated for it.
Most if not all new stuff is rated for CU-AL.

4/0 copper won't fit in 1" conduit unless u run
3 conduits, one for each line.

 

[WVBill]

There are calculators for both conduit size (how big a conduit do you need for X wires of Y size) and for Voltage drop (to figure what wire size you need to serve up X Amps, on a Y length of run) at <A target="_blank" HREF=http://www.electrician.com/> Electrician.com </A>

 

[kcbarnes]

You can only fill conduit to .40 and It depends on what he may want in the future, if 60 or 100amp that size is ok I know I wouldn't want to run 200' of 4/0 copper ($$$$).

 

[Anonymous Poster]

My mistake. I was looking in the wrong column. You can put a max. of four 4/0 wires in a 2 in. nonmetalic conduit. That's what happens when you try looking up to many things and still do your job at the same time. Opps!!

 

[djradz]

I'd skip the conduit and go with direct burial cable or individual conductors. Over the years, conduit buried often fills with moisture anyway, so your cable should be suitable for wet locations. Most wet location wire is suitable for direct burial, but not all. The only place I'd install conduit is the veritcal runs going in and out of the ground. Spend the money on larger wires rather than the conduit - it will be money well spent. Only downside with direct burial is there's no opportunity to put more cables in, in the future. However, at the length of 200 feet, I suspect you'll never be able to pull anything else in that conduit anyway unless you've used something like a 3" or 4" conduit, even if you've left a rope in it after the first installation. There's just to much friction and crisscrossing off the wires in a 200' length. Therefore, just plan ahead. Water, phone, gas, and a couple of extra #12 UF cables for turning on lights or a heater from the house.

 

[NY_Yankees_Fan]

WOW Thanks for so many ideas and suggestions; it sure gives me something to think about. I guess I should say our “ Barn” is a 12’ x 30’ shed, we just call it “The Barn” since it has a Kubota in it! I do not have a welder and do not know how to weld, so I think I will skip the extra $$ for that part of the project, but great suggestions if I did have one. I will look at the cost of 10 wire and see what the cost difference is, but I am leaning using 12/3. Guess not putting the wire in conduit only means going down 6 more inches, I will go that route and save on that cost. I will be renting a ditchwitch so the depth will not matter. I will use conduit for in and out of the ground. I like the idea of a switch to turn the heater on from the house, I may do that. Is the GFI better on the panel side/basement or in the shed and then to the plugs and lights? Now all I have to do is wait for the spring!

Thanks again for the great response.

Tom

 

[Anonymous Poster]

If you go with a receptical type GFCI, It should be in the shed. You don't need to put lighting on it, some lighting may cause niuscence trips. If you go with a GFCI circuit breaker you can go from the house. Either way you must have GFI protection on all accessible recepticals

 

[kcbarnes]

Did I just hear right, an engineer say skip the conduit!/w3tcompact/icons/shocked.gif /w3tcompact/icons/laugh.gif Most that I have worked with want 3/4" conduit run to a single outlet or some other overkill installation. I do see your point about the moisture but I have had to dig up and splice to much UF that I just like the protection of the pipe.

 

[emery]

I agree that pullingfuture wires through the conduit of that length will be very difficult. Depending on soil, the main advantage to conduit will be to protect the wire from stone abraision.

Regarding controlling heater and lights from the house, if you have a line of sight as I do, you can find $20 remote control devices that will turn on heater, lights, ect.