On 29 May 2002 at 11:45, Micro Eng wrote:

> ok..power guys...
>
> Whats the formula, given that I have the current and voltage, to calculate
> the wire size that is required.
>
> I'm talking large amounts of current...like 833Amps @120VAC
.05093 / 1,000 * 833 * 40 = 1.7 volts loss for 4/0, just over 1%.

Wire size is not determined by voltage.
How much POWER are you willing to loose in the wire?
How much VOLTAGE loss can you stand?
>
> I know for 200A, I need a 4/0 wire.
Perhaps:

4/0 wire is .05093 ohms per 1,000 feet.
For 40 feet, (20'  there and back) you get .002 ohms
@ 200 amps, the voltage drop is .4,
I'd guess this is acceptable, and perhaps over-kill.

1% of 120 VAC may be more practical, use #1 AWG for this short a run.
>
> Distances are rather short, something like 20 feet or less.
>
> anyone?
>
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>


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