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#12056 - 07/30/02 07:06 PM Need some input on a 1 mile wire run!!
Electric29 Offline
Junior Member

Registered: 03/08/02
Posts: 9
Loc: elizabethton, TN USA
I am doing a 400 amp service on top of a mountain in north carolina, it is for a house. I am not sure yet if thier is 3 phase available at the road where thier driveway starts, but I highly doubt it. I need some input on this, it will have to be inclosed in pvc conduit for protection. I was thinkink of running a high voltage feed to the top and terminating it into a transformer with 120/240 secondary, what do you all think and where can you buy a transformer of this size??? any help would be great

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#12057 - 07/30/02 07:28 PM Re: Need some input on a 1 mile wire run!!
electric-ed Offline
Member

Registered: 07/08/02
Posts: 184
Loc: Canada
I think you should do a load calculation as a first step to see if you actually need 96 kva. (240V x 400A)

The only practical way to minimize voltage drop is to run HV cable up to the house as you suggested, however it might be just as cost-effective to pay the PoCo to bring it to the house, if they will.

Ed

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#12058 - 07/30/02 07:39 PM Re: Need some input on a 1 mile wire run!!
Electric29 Offline
Junior Member

Registered: 03/08/02
Posts: 9
Loc: elizabethton, TN USA
it has to be 400amps , no choice on that. power company dont want to do it , but would for 65,000 dollars! I have did a few jobs where the wire runs were 1800 - 2000 ft and I used a constant voltage transformer for it, would this work on this long of a run , can you use more than 1? , just floating some ideas...any of yours would be great

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#12059 - 07/30/02 07:42 PM Re: Need some input on a 1 mile wire run!!
Electric Eagle Offline
Member

Registered: 04/20/02
Posts: 928
Loc: Alpharetta, GA
I also would see if the poco would get it to the house, but you may have already tried that. Also if their is any way you can direct bury the feeder it will greatly reduce the cost because the allowed ampacity for the feeder cable is much higher when not in conduit.

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#12060 - 07/30/02 08:05 PM Re: Need some input on a 1 mile wire run!!
electric-ed Offline
Member

Registered: 07/08/02
Posts: 184
Loc: Canada
More questions-
If you run the cable, what is the primary voltage? (what voltage will the PoCo give you?) A mile of 15 KV concentric neutral URD in PVC will not be cheap.

Where will the PoCo want to do the metering? They won't want to absorb the cost of the losses in the customers line.

Ed

[This message has been edited by electric-ed (edited 07-30-2002).]

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#12061 - 07/30/02 08:18 PM Re: Need some input on a 1 mile wire run!!
Electric29 Offline
Junior Member

Registered: 03/08/02
Posts: 9
Loc: elizabethton, TN USA
power company told us if they did it it would be ran like a underground sub-division, with transformers every so often, problem is customer doesnt want to pay for his future neigbors power feeder's , he wants to own the complete run, so people will not want to build where he is, power company said if they run it any future land owners could tap off of the transformers that he paid for. they also told us we could not run high voltage feeders, because our license doesnt cover it. They said we would have to run 120/240 volt triplex for them to hook it up, so this is our problem.

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#12062 - 07/30/02 08:22 PM Re: Need some input on a 1 mile wire run!!
Electric29 Offline
Junior Member

Registered: 03/08/02
Posts: 9
Loc: elizabethton, TN USA
as far as metering, if they do it it will be at the homesite, if we do it it will be on the bottom of the mountain.

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#12063 - 07/30/02 09:25 PM Re: Need some input on a 1 mile wire run!!
Steve T Offline
Member

Registered: 02/14/01
Posts: 312
Loc: Oak Park, IL, USA
Doesn't the local government have legal arrangementts with the utility company that requires them to provide power to residences within that community. Even if it is in the mountains. How do they get water? Do wells exist in mountains? How far is the run anyways? Are you planning on running OH or UG? I haven't done any calcs, but wouldn't some 750 kcmil direct burial handle voltage drop for a couple thousand feet? Ask the utility company if they would sell it to you.

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#12064 - 07/30/02 11:19 PM Re: Need some input on a 1 mile wire run!!
caselec Offline
Member

Registered: 04/14/02
Posts: 557
Loc: San Jose, CA
I don't think running the secondary this far would be practical. If you run the primary up to the house and meter at the bottom of the hill you are going to need primary metering. I think if you add up the cost of all the medium voltage equipment needed (metering, switching, over current protection and transformer) you will be better off paying the utility to do it. I don't know what the rules are in your state but in many places the first person to build a home in an new area gets to foot the bill to install the utilities but when someone else decided to build they must pay a share of the bill so the utility should give you a partial refund. Also keep in mind that anything you install ever fails the utility will not make the repairs. One possibility would be to step the 240V from the utility up to 600V at the bottom of the hill and then back to 240V just before it gets to the house. Doing this would allow you to use much less copper and would not involve installing any medium voltage equipment.
_________________________
Curt Swartz

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#12065 - 07/31/02 12:31 AM Re: Need some input on a 1 mile wire run!!
joeh20 Offline
Member

Registered: 03/21/02
Posts: 95
Loc: Tullahoma, TN, 37388
Have your local congressional representative or even a state senator in NC get their office staff to send Duke Power an informative letter regarding the Rural Electrification Act of 1939. This piece of legislations covers just this situation. Where that power providers wouldn't run lines way out in the stix to serve one or two people.
Another option, a friend of ours in Alabama has a similar situation on a mountain east of Gadsden and the nearest feed was 8000 feet at the bottom, the POCO didn't want to run for even 3 houses. He finnaly research the Phone company's responsibility to provide phone service to anyone anywhere at a the same price. The phone company had to install all the poles and service line for the nominal service fee charged everyone. They have a local monopoly and can't refuse service due to the cost. After the phone company put the poles up the POCO didn't mind using their pole to send HV OH feeder to the houses on top. He had to do his homework to get it done but he didn't pay anything but the connect fee.
I think some research may save the $65,000 tag here, I don't think the POCO is living up to the letter of their agreement to have exclusive power rights. Is it a public utility or a private membership company. They have different agreements to live by.
Post back what utility you're dealing with and maybe a friend can help over there.
_________________________
Lighting the way

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