2000' underground to house?

russplmb2

Hello all,

Im just a dumb plumber so forgive me for this question. I am wondering if it's possible to run 2000' underground to a 100 amp panel. I am told there will be a significant amount of voltage drop? Here's my situation:

I have a three phase Ag well about 2000' from where I want to put my house. The power company here wants 8000 bucks to put in a pole so I figure it will be around 10,000 by the time I get the panel, breakers, and 200' underground. I am wondering if it will be less expensive to run the 2000' from the 3 phase and put in a sub panel or a step down transformer? I figure using aluminum wire but I have know idea on sizing? I am assuming a 0 gauge?

Anybody that wants to chime in would be great. I think I already know the answer but it doesn't hurt to try and be a cheap ass. Thanks for your time.

frenchelectrican

There is couple way you can do.,

First question what voltage are you running at the AG panel ( I am not suprised that useally have 480 volts so that will get tricky with it.)


Second thing for 2 000 feet run that is I will say pretty da*med long run so talk to the POCO to run the primary from that location to the house for very good reason one) will have very little voltage drop from primay side to the transfomer near your house.

If you going to run the power from AG well you will need transfomer{s} and I will advise ya not to mess it too much due the AG meter may have diffrenet electrique rates than what the resdentail rates will be.

And the cost of conductor if you stay on after the AG meter will get ya hard.

I will come up with the figures a min due my caluations are in Metric side so give me a bit for conversion.

Merci,
Marc

P.S. look at below for conductor sizing.

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The answer will be based on NEC ( National Electrical code ) or CEC ( Cananda Electrical code ) or ECF ( Electrique Code France )

frenchelectrican

I will not edit my above commet and get all tangled up so that why I want to converted to the USA/Canada side which they use the standard size.

So let start here

For 100 amp service ( note I will sized the conductor for 80 amp which it will be 80% of full load )

Distance: 2 000 feet
Voltage: 240 volts avce netural
Conductor size : 600 KCM Copper ( for Al verison it will be 750 KCM )

Again now with 480 volts single phase

Distance : 2 000 feet
Voltage : 480 volts ( you will need transfomer will fill ya in a bit )
Conductor size : 4/0 CU ( For Al it will be 250 KCM )

Those figure will be basied on 3% voltage drop.

However you may notice why I did not include the price at all due there are serveral price to dealt with it and copper price will fluncates a bit so nothing can be written in and ditto with transfomer as well.

Merci,
Marc

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The answer will be based on NEC ( National Electrical code ) or CEC ( Cananda Electrical code ) or ECF ( Electrique Code France )

russplmb2

Thanks for your reply,

It is 480 volt three phase at the Ag well. You are right about the different prices coming from the meter too. I didn't even think about that. Is it okay to just run two legs instead of three?

frenchelectrican

The best answer will come from the electrician due there are few differnt verison of 480 volts system is and I will advise ya not to mess around with 480 volts it don't take much to get them lit up like crazy if something go wrong.

Merci,
Marc

__________________
The answer will be based on NEC ( National Electrical code ) or CEC ( Cananda Electrical code ) or ECF ( Electrique Code France )

mpoulton

If you run two phases of the 480V service out to the house, you would need 250kcmil aluminum wire to obtain a reasonable voltage drop assuming a 100A load (200A at 240V). That's a total of 4000ft of 250kcmil plus whatever you end up with for a grounding conductor. If the irrigation service is corner-grounded, you may be able to run just the two phases and avoid a separate grounding conductor if you run this as an extension of the service. You'll need a big 480:120/240V transformer, which will not be cheap.

If you ran 480V 3ph to the house, you could get away with 2/0 Al conductors for a 60A service, which provides the same total power (48kW) as 200A at 240V. You would then need a 3ph transformer and panel at the house.

It will probably be easier and cheaper to have the POCO run primary to the house.

zappa

I think you need to bite the bullet on this one. It cost me $12,000 for a 1700' primary run AND I had to do all of the underground conduit work so consider yourself lucky.

Overhead would have cost me $40,000 for a 2000' run.

kbsparky

#4/0 type URD cable would provide plenty of power with a reasonable voltage drop. This cable is readily available at most supply houses. I can get it for about $2.15/ft. 2000 feet would set you back $4030. Better get it quick, as Aluminum commodities are spiking in price 25% or more even as we speak.

Most URD is dual rated as USE or RHW or that should not be a problem.

You would only need to connect it to 2 of the 3 phases at the originating panel.

A transformer set at the house would then drop the 480 to 120/240 Volts, and would be a separately-derived system. As such, you would install the appropriate ground rod(s) or other elements of a grounding electrode system.

You could use a 60 Amp fuse or breaker at the pump house, and set a 25 kVA transformer at the house.

If you don't think you'll need the entire 100 Amps, then a 15 kVA transformer would provide a continuous 62.5 Amps, with only a 35 amp breaker at the pump house required.

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AllanJ

Since you already need a transformer (480 volts to 120/240 volts), you might look into a two transformer system: 480 to 2400 volts at the pole and 2400 to 120/240 volts at the house.

Now, I don't know the rules and wire types for running this underground; you do need to follow the rules of primary voltage as opposed to secondary (600 volts and under) voltage.

A hundred amps at 240 volts equals ten amps at 2400 volts. Using 10 gauge wire the round trip (a little under under a mile) is 5 ohms, where 10 amps will drop about 50 volts which, out of 2400, is around two percent.

Because you are not altering the service from the power company, you are not obliged to hire them at their rates to do the installation. But, to avoid the higher cost of 3 phase transformers, you will be drawing up to 50 amps at 480 volts from 2 of the 3 phases at the supply using a single phase transformer,and you will need to be sure that this imbalance is tolerable by the POCO.

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russplmb2

I have one more option to consider as well.

There is a single phase pole about 10 feet from the three phase pole. This pole is for the neighbors house. I know the setup is kind of weird. I guess this property used to be a big ranch and it was split up and sold. My neighbor bought the piece he us on but did not want to buy the Ag well so there is an easement road from our property to the Ag well. His house well is about ten feet from my Ag well.

Anyway, I am just wondering if it would be easier to run direct burial from his pole(single phase). No transformers this way I guess. I apologize that I didn't mention this sooner. If this is an option would the 4/0 still be a good size to run and how do I find out if direct burial is acceptable?Ask the inspector? Does this even need to be inspected? The only reason I ask is because in the plumbing world I can run water lines wherever I want on my property without inspections. Thanks again for everyone's replys.

carmusic

try to found high voltage cable 10awg 2.4kv, it will be probably be more expensive than the 4/0 cable

gregzoll

You are better to put in a transformer halfway, on that long of a run. Here is what someone that is advertising 1,000 feet on ebay http://www.ebay.com/itm/1000-750MCM-...-/160631593397

So, do you have $36,000.00 to pay for 2,000 feet of wire?

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mpoulton

Keeping it to 600V to ground would allow the use of normal 600V-class wire and wiring methods. A center-grounded system with 600V to ground on each leg would have 1200V between legs and draw 40A max. You could use #6 wire, or #8 if your calculated load is less than about 150A (at 240V). If the service is corner-grounded, you could use a pair of buck/boost transformers at the service end to boost the 480V phase voltage to 600V. This would save quite a bit of money over using regular transformers.

But I'm not sure I can really advise you to install a system like this as a DIY project. 600V to ground is nothing to mess with casually.

AllanJ

I must be missing something. I never thought that putting in a transformer halfway had any benefit unless you needed to tap off at that point. I always thought it was better to put the step up transformer at the start of the run and the step down transformer at the end.

The longer the high voltage portion of the run, the less energy lost in voltage drop given the number of amperes needed at the final voltage.
Isn't 600 volts hot to ground and 1200 volts hot to hot classified as a 1200 volt system? An aside: the voltage rating of a 3 phase system is the voltage from phase to phase.

__________________
The average homeowner who lost his house in the Oklahoma tornadoes should move for good and not rebuild. Too much complexity watchdogging the contractor. Too much a chance to be defrauded.

AllanJ

Does that single phase pole belong to the neighbor or is it on his property? If the power company owns the pole the power company may have the right to give you a line from that pole. Underground or overhead would be the final choice of the power company.

Yes it would need a permit and inspection. Improperly installed electrical lines can kill someone; improperly installed water lines won't. (Some water companies require inspection of all lines attached* to their systems to ensure against backflow of contaminated water into the water mains.)

* Using the bonding rule; if A (out in the pasture) is attached to B and B is attached to C (the water main) then A is attached to C.

__________________
The average homeowner who lost his house in the Oklahoma tornadoes should move for good and not rebuild. Too much complexity watchdogging the contractor. Too much a chance to be defrauded.