I need 40 amps at the end of the 1000 ft.What size wire do I use.If there is a formula I would like to have it.
2007-02-19 10:01:00 · 6 answers · asked by Chester J 1 in Home & Garden ➔ Maintenance & Repairs
The answer is 3/0 copper wire for a 240V 40amp circuit with a 3% voltage drop. Here is how to get the answer:
Formula: V = (2K * L * I) / D
where V=Voltage drop (up to 3% for feeders)
K=resistivity for copper @75 deg C (12.9 for copper; 21.2 for Aluminum)
L=One way length of conductor in feet
I= current in conductor
D=Cross-sectional area of conductor (in circ mils)
A little rearranging>>>
D=(2K *L*I) / V
D= (2 * 12.9 * 1000 * 40) / (240 * .03)
D=1,032,000 / 7.2
D=143,333 circ mils
Look up conductor properties in National Electric Code.
Next size above is 3/0 copper.
If you were to use 2/0 copper your voltage drop would be 7.75 volts or 3.2% a little high but probably OK
2007-02-19 10:52:17 · answer #1 · answered by Anonymous · 3⤊ 0⤋
First you should probably consult an electrician.
the formula is still Ohms law. V= I*R You know the Voltage at 110V or more likely 220V the Current is 40A. But look on the wire itself (you should be using 4 or 6Ga wire) it should say it's resistance per 100 ft or per 1000ft. but really copper wire resistance shouldn't be a factor with only 1000ft, it's much more running it safely that you should be concerned about. If in doubt use thicker wire, even 2Ga or 0Ga wouldn't be a bad idea.
2007-02-19 18:21:04 · answer #2 · answered by jeepguy_usa 3 · 0⤊ 0⤋
you would normally use a # 8 gauge copper wire but with a run like that you would need to derate the wire so you would have to use a #2 gauge copper wire and a 40 amp breaker/fuse for roughly every 300 ft you want to go down a size
2007-02-19 18:31:57 · answer #3 · answered by brndnh721 3 · 0⤊ 0⤋
That's a long run. I gave you a link to a voltage drop claculator. For that run, I'd use 4/0 aluminum. Copper will put you in the poor house at today's prices.
If there's a power pole close to where you want the juice, it might be simpler and cheaper to pull a permit and install a whole service.
2007-02-19 19:34:38 · answer #4 · answered by Hank 3 · 0⤊ 0⤋
Ohm's Law is really simple. It Says that:
Amps = Volts x Resistance. To decide your Resistance...it gets complicated unless you have a DVOM.
So to make it really simple, you would most likely need a 1-gauge cable or fiber-optic cable to do this. Just remember that the longer the wire... the more resistance and alot of heat. Be careful. Fuse the wire in the beginning, middle, and end of the wire so you don't light a fire in whatever you are powering. GL
2007-02-19 18:07:49 · answer #5 · answered by nekolon88 1 · 3⤊ 1⤋
u lose 10
i think
but
u will have high metaphoric rat(muscles)
2007-02-19 18:05:24 · answer #6 · answered by funny_girl 2 · 0⤊ 0⤋