Sizing for overhead distance

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J82

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Have a non profit we do work with that they are looking to add power to there property. Problem is power company gave them a ridiculous amount to turn power on to the existing lines that are about 300' from where they want it. Other side of the property they can get power turned on at reasonable price. But that is about 3000' away. Going all overhead I know we would have to add transformers for voltage drop this is just about above what we normally do. Just a 120/240 100 amp service is all they are looking for can anyone point me in the right direction?
 
It's possible to take service from the utility at their distribution voltage (15 kV class) if they will allow it and are willing to install pole-top metering CT and PT at the point of service. Running a single-phase OH line on wood poles for 3000 feet might not be as expensive as you think. Far cheaper than running the same voltage underground. Then a pole-mounted transformer at the last pole. Lots of unknowns, but this is one possibility.
 
David Castor said:
It's possible to take service from the utility at their distribution voltage (15 kV class) if they will allow it and are willing to install pole-top metering CT and PT at the point of service. Running a single-phase OH line on wood poles for 3000 feet might not be as expensive as you think. Far cheaper than running the same voltage underground. Then a pole-mounted transformer at the last pole. Lots of unknowns, but this is one possibility.
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Take note-- I believe that you will own the wooden poles, and will be responsible for their maintenance. Get the good ones!
 
From what I was told we wouldn’t be supplying the poles just installing which I’m not worried about that. We have a guy that drills and installs them no problem. As far as using utility distribution voltage. Not sure about that one was told they have 120/240 in the area. I know the area doubt they have anything higher nearby most a residential area around.
 
I'm talking about the high voltage line the utility runs down the street. Probably 12.47 kV, 12 kV, or something similar. Setting wood poles would be much cheaper than steel poles. But the first step is discussing this with the utility to see if this is even an option they would consider. It's technically feasible, but might not might their standards. Utility metering departments are generally not the most flexible and creative group of people you will encounter..
 
Like David said, might be worth looking into what voltage options POCO has. I highly doubt they will do a MV service for that low a demand. MAYBE they will do 480 in which case that may be worth it as you will only need one transformer at the end to step down to 120/240. Many POCOs these days won't even do that as they don't want oddball stuff out there, but worth a try.....if you have to do a step up / step down, i have quite a bit of experience and have two options I would suggest looking into (I have done both):

1. Standard 15 kv class step up / step down setup. I have done UG with CN #2 cable. For most of us UG is the way to go as setting poles and doing that type of OH work is a bit of a specialty. I know you said u got a guy who can set poles so maybe that is an option. IMO UG is much simpler nicer and cheaper and within the skill set of pretty much any electrician (except making up the elbow connectors which scares people but it's not a big deal). You can get surplus + used transformers pretty cheap, probably 7.2/12.47 or 7.62/13.2kv, try Solomon, Maddox, and T&R electric.

2. Do a 2kv step up step down with 2 kv PV
wire. Probably you will only need like #10 CU (this is what I have serving my house, 1900 feet but it's #12).. set it up as an MGN and you only need (1) 2kv conductor and the grounded conductor can be standard 600v rated. 3/4 conduit ! Of course you will need custom transformers, but that's not a big deal, try Hammond and olsun, they can make that for you. Of course you will pay more for transformers because of the special voltage you won't have any used/surplus options, but the wire and conduit is cheap as crap.
 
I understand what David was talking about voltage wise guess I just didn't sound clear on my end. Guess I will start over with the little bit of info I was given, trying to explain things on here can be tough I am sure you all understand. POCO supposedly only has 120/240v on the road residential area but not a lot of houses on it, I will have to take a drive later on and take a look myself. They where told they can put there new 120/240v 100 amp service within 75' of the road (just going to give them a meter and disconnect there) then do whatever they want from there obviously. But where they truly want the power is the other end of the property which is about 3000' give or take. Will be all overhead, my biggest problem is our company mostly does commercial new construction and repairs and sign/lighting repairs. We don't usually do the pole mounted transformers and figuring voltage drop for something of that kind of distance. I am assuming with this low of a voltage probably going to need 2 transformers just to keep the voltage usable at the end but not 100%. When its all said and done there amp draw is going to be minimal if I had to guess maybe max 30 or 40 and that would only be a couple times a year. 99% of the time probably 1 security light.
 
If you only need 30-40 amps and intermittent use, then maybe something with a pair of 7.5kva 600 volt transformers feeding 4/0 triplex, maybe cerapus, would work. Keep in mind the exception in 250.30 that allows the neutral and EGC to be combined.
 
J82 said:
When its all said and done there amp draw is going to be minimal
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Real estate developments may justifies utility expansion into remote areas, but no foundations could be built on a 12kv sub surface path.

Remote options typically include wind mill / propane generators, and/or solar backup batteries, good for a typical day of residential load, excluding large appliances.
 
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