Installing Electric To The Barn

[MossRoad]

If you decide to only run one circuit out there like it sounds, you can put X10 appliance outlets and light switches in some of the boxes. These can be controlled by several different types of remotes from your house or garage. They send signals over your power lines. Each module is addressable. That way, you wouldn't have to run extra wires. So, you could control the lights from the garage or the house, or a keychain remote without any special wiring. I use one to run my pool pump all summer. It works great.

 

[Phred]

interesting timing on your question.

I have a well that I ran wire to ~300 feet from the house. Being a cheapo I looked at the wire sizes and did the calculations and said sure 10 /3 UF will be more than enough for what I need........ Wrong.
One year latter and I need more juice for a new load. Maybe could get by with the 10 gauge but it would be close. The voltage drop would probably reduce the pump life.

The good news is I had the presense of mind to run the UF in conduit. So rather than dig up the 300 feet of wire I will be pulling an additional 8/3 UF through.

But it will be a pain in the ^$$. So this weekend I will be trying to pull that 8/3 UF through the conduit and thinking of all that money I saved using 10/3 rather than 8/3.......
but of course now I will have paid for the 10/3 and the 8/3!

Moral of the story, Figure out what you need in power. Multiply by at least 3 and then run it in one size conduit larger than the specs call for. You will be glad latter on.
Why the bigger conduit than the specs call for? Ever try to pull 8/3 or bigger through a conduit for a few hundred feet? Time for the tow truck or logging winch...
Also watch the number of 90s. More than 2-3 90s and you will likely be digging it up again any way.

Fred

 

[NY_Yankees_Fan]

If you decide to only run one circuit out there like it sounds, you can put X10 appliance outlets and light switches in some of the boxes. These can be controlled by several different types of remotes from your house or garage.


Moss,

Where did you get the units at, and how much?

Thanks

Tom

 

[MossRoad]

I got mine at x10.com and smarthome.com. I have lots of that stuff around my house. A heavy duty X10 110v 20AMP outlet is about $50.00. Incandescent light switches in bulk for $6 or $7, singley, $8 or $9. A simple table top controller that plugs into a wall outlet back in your house is about $10. That would get you going.

You could get more elaborate with timers, controllers, computer control, etc..., but that might be a discussion for another thread. There's one over at CountryByNet. <A target="_blank" HREF=http://www.countrybynet.com/forums/showflat.php?Cat=&Board=fix&Number=7013&page=0&view=collapsed&sb=5&o=&fpart=1>If you're interested, click here.</A>

 

[Crazykansasan]

I'm confused? Why did you run UF in conduit. It is my understanding that UF is underground feeder and is made for direct burial. I've been told that placing UF or MN in conduit prevents heat dissipatation and may cause wire failure.

 

[Phred]

Did not need to its overkill. Your right it is designed for direct burial.
Started with the UF and decided to run the conduit once I had the wire already.
My understanding, (not a wire expert), is that the main difference between UF and THHN or romex is the insulation is thicker and UV resistant.
If you look at a section of UF the insulation is much thicker than THHN.

How could it cause over heating? For a long run like this the resistance per unit length is small for the current used. The reason you use a larger wire is to prevent a large voltage drop. So the heat generated per unit length is very small.

For example a 1 HP (220-240V) well pump could be run off 12 gauge for a short run. However, at 500 ft from the source 10 gauge is needed so the voltage at the pump is not dropped to much. But heating in any section of the wire is very small, lets do the math:

10 gauge wire has a resistance per 1000' of 1.018 ohms.
So our 500 foot case would be 0.509 ohms.
Lets assume that 1hp pump actually consumes 1200 watts due to power factor, etc... rather than an optimistic ~700 watts. The voltage drop along the wire would be about 5 volts for this case.
Power loss in the wire is then on the order of 12 watts. For the entire 1000 feet (500 feet down and then back).
A 12 watt heater over the length would not even be noticed no matter how good the insulation is ....IMHO.


Fred

 

[Phred]

Update.

Turned out not to be as painfull as I had thought.
Key was the conduit and the fact that I up sized it a bit.

For #8 most charts will indicate ~1" conduit would be adequate.
I ran 1 1/2". Cost was not much more and it made pulling out the old 10 gauge UF and swaping it with 8 (THHN this time) pretty straight forward.
A little bit of friction multiplied by a couple hundred feet and a few 90s makes for a work out.

 

[Anonymous Poster]

The only difference between THHN and say MTW is the THHN has a coating of teflon on the outside. MTW and THHN are both rated at 90degC

 

[djradz]

Hey Kevin, Engineer by day, homeowner by night! /w3tcompact/icons/grin.gif/w3tcompact/icons/grin.gif Actually, I work for the local electic utility and we direct bury all the time. Feeds from transformer pole to customer, underground distribution circuits, and circuits in substations. You just need to try to be sure to minimize the rocks. Even at that, we put plenty of circuits in gravelly locations. I just think in this case I'd spend the money to double the size of the circuit or install a second or third circuit, rather than installing conduit that I won't be able to ever pull anything else through again anyway.

 

[Inspector507]

Ray,
MTW is not recognized as a suitable conductor for the run of the mill wiring to the barn in conduit. It is Machine Tool Wire. They both could have a nylon coating which would make them 90-C.
I can tell you what I would run, if I were doing it.
Run 1 1\4-1 1\2 inch PVC 18-24" deep. Pull 4#6 THHN conductors, hit a sub-panel and call it a day. If you feel the #6's are not enough in the future, you should be able to pull them out and larger ones in. But that's just what I would do.

Jerry (27 years in the trade, 14 inspecting)