Long distance electrical line run

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lgmagone

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My dad and I own adjacent properties. Both are large.

He has power to a building that he owns. I would like to setup a camping site with a power pedestal and perhaps install some amateur radio communications equipment. I would like to have 20amps at 120V. 240V would be even better, but not required.

It is about 1800 feet from the building that has power to the location that I would like to install the power pedestal.

What is the least cost method of accomplishing this? The power main is approximately 2000' from where I would like to install the power pedestal, so a power main extension is not practical at this time.
 
A pair of transformers; one to step up the source voltage, say from 240v to 480v or 600v, and another to step the voltage back down.

I suggest a 120/240v transformer and a small main-breaker panel at the load end, and ground the neutral as you would with a service.

The higher voltage will allow for smaller wire for a given voltage drop when under load, and likely be cheaper than 2000' of larger wire.
 
Using Southwire app with these parameters:
1800'
120 volts
3% VD
20 amps
Copper
I get 400 kcmil with 2.83% VD.

For 240 volts it's #3/0.
 
infinity said:
Using Southwire app with these parameters:
1800'
120 volts
3% VD
20 amps
Copper
I get 400 kcmil with 2.83% VD.

For 240 volts it's #3/0.
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Notice that when you increase the voltage by a factor of two, for the same wire size, you get a double benefit on %VD (reduced by a factor of 4):
The current is cut in half for the same power, and the voltage you are taking a percentage of is doubled.
 
I get #2 direct buried aluminum conductors for 10a @ 240v for 2000' with a 5% VD. Upping that 30a gives 250 MCM aluminum. Stepping it up to 600 volts puts you back down at number 1 aluminum again.

Cheapest method is going to depend on whether or not the camping site needs 24/7 power, and how much your future loads are going to be.

20 amps at 120 volts is only 2400 volt amps. 30 amps at 240 is 7200 volt amps.

Because the distance is so long, and the load is small I would be inclined to bypass having transformers and run larger cabling. If your site ever needs to grow Beyond Your current desired maximum output of 30 amps at 240 volts, the larger cabling that is already installed can easily be tied into step-up and step-down Transformers... If you run smaller cabling off the get-go with a step-up step-down and wish to expand in the future, you're going to have to redo that 2000 foot run of cabling. Depending on where you live, you may want to use conduit anyway as critters could damage your cabling.

If you are going to be there one or two days once a month, a portable generator maybe the cheapest option.

Eta: If this site ever has the possibility of an RV hookup or two, you would want at the very least the 30 amps at 240 volts.
 
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Are you sure you need 20 amps? How about planning for a smaller load, with either a generator or a battery and inverter for the brief times you need a larger load? Or even just battery and inverter to supply all the loads, w/ power for the battery charger? It all depends on the load and the time used.

Also, I learned at my place that direct burial is wasted money with the chewing critters that live underground.
 
Barbqranch said:
Are you sure you need 20 amps? How about planning for a smaller load, with either a generator or a battery and inverter for the brief times you need a larger load? Or even just battery and inverter to supply all the loads, w/ power for the battery charger? It all depends on the load and the time used.

Also, I learned at my place that direct burial is wasted money with the chewing critters that live underground.
Click to expand...

Very true. is better to do the job once and over engineer a bit it than to try to find, dig up, and repair a fault in an underground feeder cable of that length.

I've done work at a commercial property that ran all UF from light pole to light pole. about every six to nine months, one of their 480-volt streetlights would be out, courtesy of a grenaded underground conductor that was put in a poorly backfilled trench.

If you think your initial installation cost is too high, price what directional boring 250ft under a parking lot costs.

In any event, it depends on how much the trenching will cost, and using aluminum over copper is going to save ? .
 
running 2000 feet of rigid underground is not cheap either. the terrain might even make it very problematic. i am thinking PVC is not a lot better than UF critter wise.

poles are a fairly cheap way to run wiring overhead if there are not a lot of trees. but that can have critter problems too.

there may not be a perfect solution.

personally, I would not worry all that much about what might happen down the road. If the decide they need more juice down the road, they can deal with it then. If a critter eats the UF cable, they can deal with it then.

realistically, if it is just a few days or weekends a year, a generator is probably the only cost effective solution. go to big orange and get a garden shed to put it in that can be ventilated so it is less noisy and you have a place to store the diesel.don't store gas out there. too dangerous.
 
petersonra said:
running 2000 feet of rigid underground is not cheap either. the terrain might even make it very problematic. i am thinking PVC is not a lot better than UF critter wise.

poles are a fairly cheap way to run wiring overhead if there are not a lot of trees. but that can have critter problems too.

there may not be a perfect solution.

personally, I would not worry all that much about what might happen down the road. If the decide they need more juice down the road, they can deal with it then. If a critter eats the UF cable, they can deal with it then.

realistically, if it is just a few days or weekends a year, a generator is probably the only cost effective solution. go to big orange and get a garden shed to put it in that can be ventilated so it is less noisy and you have a place to store the diesel.don't store gas out there. too dangerous.
Click to expand...

This.
 
A combo power solution might also be optimal.

1. Generator
2. Lithium Ion power station.
3. Solar cell.

Generator for when you need full power, and to recharge the Lithium. Lithium Ion for lower power levels, lower duty cycles, and when you would like some peace and quiet...AND power. Solar cell is sort of optional as you'll probably want smaller portable versions, so it cannot get anywhere near your spec, but can keep minimal electronics running and provide some recharge options for the power station.

Consider a propane generator. The propane can do double duty as fuel for a portable heater.
 
I know a few places in JA that have solar and batteries with generator they run only if needed.. possibly twice a month except when they have parties... not cheap to set up but they looked at cost of running power when they built... figured three years it would be paid for...
 
We do a lot of long runs. At the distances you're talking about, it is essential to know exactly what your loads are. A couple extra amps one way or the other can have a fairly large effect on voltage drop.

For what you're trying to do, at that distance, I'd recommend a generator instead. The cost of installation would probably pay for the cost of several generators.

If you're still determined to run wire for this, you can't beat the value, the dollar/amp ratio of aluminum in long runs like this. I would lean towards buying a reel of cablecon if I was approached with this project.
 
Might be worth stepping up to 600 volts, then use a 600->120/240 on the far end. 3KVA transformers should be pretty cheap. All you would need is #12 wire. Use the 250.30(A)(1) exception #2 and you would only need two conductors. If you dont need code compliance, use a mini trencher such as the brown bed edger with a 1" blade:

http://brownproducts.com/Products/BedEdger.htm

3/4" PVC fits in the groove, super low impact. Thats what I used to go 1900' thru my woods. Could use IMC and be code compliant, gunna cost a lot more than PVC of course, but still might be worth it over the huge mess of conventional trenching.
 
Even running 240 volts and then a 120/240 transformer at load end is worth consideration. @ 2000 VA that is only 8.3 amps, would need larger conductor than if 480 or 600 V but only need one transformer instead of two. More important is figuring out what kind of voltage drop can be tolerated vs strictly going with 3 or 5% mentioned in an informational note. If you have a RV and start the AC, you will have a temporary voltage sag even on much shorter runs in most instances because of the starting current of that AC.
 
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