Underground Wiring

Hello, I just purchased a 6 acre country property in West Texas and am building a small apartment (580SF). I didn't do a lot of research on supplying electricity to the apartment and had the electric company place a meter on the pole about 200 feet from the apartment. My intention was to trench and bury the service wire. Now I browse through Home Depot looking at wire and see some costing $5-6 per foot. Wow. Can anybody tell me what size wire I require to run this service? My intention was to in the future add another 1500 SF main home to this structure. I thought I would power the entire thing from the box in the apartment, but if the cost is out of sight I'll run service for the small apartment and worry about power for the main house later when it's built (2 years). I have another pole that's about 120 Feet from the structure so I could possible eat the cost ($580) for the initial meter and have one brought closer. Does this make sense? Can anybody tell me what I'm looking at.
Thanks
Dave Worried out West
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"dgreen368" wrote...

I hope this was a clue to stop now and start doing some proper planning before you go any farther.

Not until you decide the service amperage, the length of your run, and what wire type is accepted by code.

No
A mess! A potential catastrophe! A money-pit in the making. Do yourself a huge favor and call an architect, an electrical engineer, the utility company, or all of the above. They should be able to provide some ideas that will save you money in the long run.
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Once you figger out the power needs, keep in mind you can use smaller (cheaper) wire if you go overhead. Also, it sounds like you were pricing copper. Aluminum is perfectly acceptable in a service entrance application.
--
Steve Barker


"dgreen368" <u31625@uwe> wrote in message news:6d8e091a068a8@uwe...
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The above advice is understandable but probably exaggerated. Sounds like you'll need at least a 200 amp main panel to service the small apartment and main house together. You'll probably need no more than a 100 amp subpanel for the apartment. Wiring underground is certainly the more pleasing way to go in the long run, but you will need at least 2" PVC conduit. It will be hard to pull wire through the full 200 feet even if it's a straight line, so I'd consider a splice box part way. The wire that goes through the conduit should be three separate braided cable type wires because the single 3 wire bundle will be too difficult to pull. Aluminum is acceptable in a service entrance application as said, but copper is certainly more durable, and once installed you will be happy you used copper. If natural gas is available, I'd bury a gas line in the trench as well (and a water line too). Using natural gas or having a propane tank for home and water heating and for cooking will reduce your amps needed significantly, although A/C will still draw a lot too. You should consult with an electrician though, and not just take advice from here.

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ACTUALLY, aluminum is used for almost all service entrances. At least here in the midwest. There's nothing more durable about copper, and once it's installed, he'll not know the difference, so he'll not be happier or sadder with either.
--
Steve Barker

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Dave,

Generally, you need 4/0 aluminum cable or 3/0 copper cable for 200 amps. Copper is really expensive right now, and Aluminum is typically used most for underground services anyway. You just need to use an antioxidant paste on the cable ends where it connects to your breaker panel.
However, different areas have different requirements, so check with the agency that governs electrical permits in your area (You'll need a permit to install a panel in the apartment anyway). They'll be able to tell you what wire size and type you need.
Around here (Washington State), we typically use a cable designated for underground service entrances. It's usually on a huge roll sitting on the floor in the home centers (usually too large and heavy for their wire racks). It consists of three individual 4/0 aluminum cables, one of which has a stripe to indicate it is the neutral line.
I recently installed a new underground service at my in-laws house. I used aluminum there too, except for the short feed between the meter on the outside of their house and the panel on the inside. 3/0 copper was much more flexible to feed through the conduit bends than the aluminum cable would have been.

We had the power company install a pedestal in the ground. Then we have separate underground lines (and the associated service entrances) that run to our garage, our house, and our pumphouse. The three buildings are completely separate services, with only the electric meter in common (on the pole out at the road).
We used this approach because the various buildings were constructed over a period of many years and we didn't want to worry about trying to feed one building off of another. It also allows us to have full 200amp services at each building, and makes it easier to add new services in the future. We had a mobile home on the property for a few years that tied into the pedestal also.
I'd recommend you check with your electric company. They usually have an engineering evaluation for the new entrance. They'll come to the site, see what you have planned, tell you what requirements they have (separate from the state electrical requirements), and charge you a few hundred dollars. :) It's all rather expensive, but you only do it once.
We had a couple of places on the property where we installed conduit before we actually ran the cable. One was under a driveway heading to the building site before we actually started building. We used 4" grey PVC, with the appropriate bushings on each end to avoid cutting into the cable. The conduit sat in the ground a couple of years before we actually dug down again and ran the cable through it.
Anthony
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"It will be hard to pull wire through the full 200 feet even if it's a straight line, so I'd consider a splice box"
I don't think Alan ever pulled any wire through conduit or he wouldn't have made the above statement. I pulled 400 foot of 4/0-2/0 aluminum triplex underground service cable through 3" pvc conduit by hand. It pulled pretty easy even though I am not a big guy. If I had it to do over again I would probably hook to a riding lawn mower and make it even easier. Two hundred feet should be a piece of cake. Check with the power company and they will tell you what you need. Most utility companies guarantee a certain voltage at the meter so try and get the meter as close to the point of use as possible. More volts are always better.

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It's possible you are missing a easier/cheaper way.
Here, I put in the 2" pipe and also beside it 2, 1" pipes for cable and phone. The meter is on the end of the house and P&L supplied and pulled the wire from the pole to the house/meter.
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I agree, it shouldn't be a big deal to pull cable through 200 feet of conduit. We pulled three conductor 4/0 aluminum cable through 70 feet of 4" conduit that had two 45 degree bends. It went very easily. Assuming you make a few preparations, it shouldn't matter if it's 200 or 500 feet.
1. Use larger conduit. It'll be a LOT easier to pull 4/0 cables through 3" or 4" conduit than it will through 2" conduit. This would also let you upgrade to larger cable in the future if the need ever arose.
2. When you install the conduit, feed a "pull rope" through each section so the rope is available at each end of the conduit.
3. If the conduit is already in, and you forgot to install a pull rope, tie a piece of cloth big enough to loosely fill the conduit to the end of a string. Then use a shop vac on one end to suck the rag and string through the conduit. Then tie the string to a rope and pull that through. You can then use the rope to pull the cable.
4. Put a little "cable lube" on the cable before you start pulling. This is a waxy substance that really simplifies cable pulling, especially in tight situations. Just don't get it on your hands or gloves or you won't be able to hang on to anything. :)
5. Use electrical tape to secure the pull rope to the end of the cable. Try to make the end of the cable "taper" a bit with the tape so there's less likelihood of it catching on the conduit joints. Squirt a little cable lube on the end, then have one person "push" the cable in the conduit, while another "pulls" the rope from the other end. The person pushing should do most of the work, the rope is mostly to help guide the cable. Don't pull too hard or you may pull the rope loose from the cable.
Shouldn't be any problems, but if it seems to get stuck, just pull the cable back a bit and try again. If you have a bend or two, it make take a bit of jiggling to get the cable through the bends. Worst case, you can pull the cable out and start all over again.
Good luck,
Anthony
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Thanks for all of the information. I'm going to slow down, contact the engineer at the utility company and have him come out and review the electricity supply point options with me. Then I'll involve a licensed electrician to work with me to develop a plan that fits my budget and my willingness to put in the sweat work. Through this post and others here I've learned a heck of a lot. Thanks again. ..
dgreen368 wrote:

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