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Wire for a 480v 3p run of 800 feet?
By thane, Section Hydro Posted on Mon Jun 22, 2009 at 04:22:52 PM MST
I need to run 800 feet from turbine to batteries... and I have an opportunity to get some cable.

I have an opportunity to get some cable at a great price.
It's 3 conductor 10 awg. Direct bury, armored.
I need to run 800 feet from turbine to batteries... will this work?
I don't have the turbine yet... Will I need ground or neutral?

Wire for a 480v 3p run of 800 feet? | 10 comments (10 topical)

Wire for a 480v 3p run of 800 feet? (3.00 / 0) (#1)
by wooferhound on Mon Jun 22, 2009 at 10:42:39 AM MST

How many amps do you think you will be pushing through this wire run ?
the voltage doesn't help much . . .

W o o f -={(

Re: Wire for a 480v 3p run of 800 feet? (3.00 / 0) (#2)
by thane on Mon Jun 22, 2009 at 11:12:30 AM MST

I think I will be limited to about 8 amps... no?

[ Parent ]

Re: Wire for a 480v 3p run of 800 feet? (3.00 / 0) (#3)
by ghurd on Mon Jun 22, 2009 at 11:24:42 AM MST

The turbine will determine if it is suitable.
It would be OK for a very low power turbine,
Or a high voltage turbine,
Or a high voltage AC turbine being transformed to a lower voltage near the battery,
Or...

That 800' is a long ways to run. #10 is not very big.
G-

Re: Wire for a 480v 3p run of 800 feet? (3.00 / 0) (#4)
by wooferhound on Mon Jun 22, 2009 at 11:34:54 AM MST

According to the voltage loss calculator on this page
http://www.powerstream.com/Wire_Size.htm
you would lose about 14 volts on a 800 foot run of two 10 gauge conductors pulling 10 amps.

If the armor is conductive you could pair up 2 conductors of your cable for the Positive side, and the last conductor plus the armor for the Negative side. This would halve the voltage loss.

I have the Negative side of my Solar Power grounded but it is not necessary. If your turbine is 3 phase you may rectify and combine the phases onto 2 wires before you send the power on the 800 foot trip, or you could send all 3 phases down the 800ft line which will require 4 conductors. That may work if your armor on the cable is conductive.

W o o f -={(

Re: Wire for a 480v 3p run of 800 feet? (3.00 / 0) (#5)
by Airstream on Mon Jun 22, 2009 at 12:31:00 PM MST

Wire run calculates to 2.96% voltage drop at 10 amps, a nearly perfect spec. With 5 amps the drop is half that.

True 3 conductor will have three 10's and a ground. If you are seeing 2 10awg and a ground wire check if the ground is the same gauge as often they reduce its size.

What I am hoping to hear is the cable is NEW and UNUSED, it would be hard to justify the labor of burying 800' of used cable because of possible future problems. If it is used and cheap enough there is always PVC conduit...

480V means it will always be searching for any excuse to leak & short possibly with much less 'cause' than with lower voltages.

Re: Wire for a 480v 3p run of 800 feet? (3.00 / 0) (#6)
by thane on Mon Jun 22, 2009 at 12:47:02 PM MST

Yes, it's new. I may be able to get a "LOT" of it... enough to run multiple legs.

[ Parent ]

Re: Wire for a 480v 3p run of 800 feet? (3.00 / 0) (#7)
by Airstream on Mon Jun 22, 2009 at 05:04:47 PM MST

:::drool:::

[ Parent ]

Re: Wire for a 480v 3p run of 800 feet? (3.00 / 0) (#8)
by wildbill on Mon Jun 22, 2009 at 07:55:46 PM MST

cheap it dosn't burn your fingers when you pick it up,#10 under ground big bucks.
good find.

[ Parent ]

Re: Wire for a 480v 3p run of 800 feet? (3.00 / 0) (#9)
by dnix71 on Mon Jun 22, 2009 at 08:04:31 PM MST

Whoever is selling you the turbine should be responsible for wiring it to code.
480v ac is immediately lethal. There were some unfortunate people at bus stops in Miami a few years back that fried because some asshat contractor couldn't properly ground the 480v step down transformer used for lighting the bus shelters.

The ground there is solid coral limerock. You can't drive a ground rod in it, and even if you did, rock doesn't carry away stray current very well.

http://www.justnews.com/news/4444128/detail.html

http://www.justnews.com/news/4441192/detail.html

He was not licensed and the county did not require a license or permits or inspections.

Do yourself a favor and demand a licensed, inspected job.

Re: Wire for a 480v 3p run of 800 feet? (3.00 / 0) (#10)
by thirteen on Tue Jun 23, 2009 at 09:45:32 PM MST

As a safty thought if you are the only one working on the system and you understand 480v 3 phase it would probably be ok. But if there is a chance someone else will work in it please label it correctly. A simple lock on a power box may help. No insult intended. Alot of people don't uinderstand it and it kills in a heart beat. I work with it every day and it is dangerous. Just as an idea.

Wire for a 480v 3p run of 800 feet? | 10 comments (10 topical)

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