According to Meat Plow :
On Mon, 09 Jul 2007 17:10:50 -0500, dpb wrote:

Toller wrote:
"Jeff Wisnia" wrote in message
...
Henry wrote:
I was wondering what cable size to use for wiring a 125V 12 amp fan that
is 100 feet away from the breaker panel.

Thanks.

You should be able to use 14 gauge wire.

It'll drop about 4 volts at 12 amps over that length, but that shouldn't
worry a fan much.

You could use #14, but there will be a lot of VD at startup, ...

How did you determine that, and how much, specifically, are you thinking
is "a lot" for a fractional hp fan motor???

Not to nitpick but wouldn't a motor drawing 12 running amps (if the OP is
correct) be in the realm of a couple hp? If I recall my 5 hp compressor
motor draws around 12.

Not at 120V it don't. A "true" 5HP motor will draw somewhere around 40A
on 120V, or 20A on 240V. (On motors = 1HP, count on approximately
900-1000W/HP because of inefficiencies. Yes, I know, the exact conversion
is 746W/HP, but no motor is 100% efficient)

At 120V, a standard 12A motor is probably between 3/4 and 1HP, tho possibly
as low as 1/2HP. Not lower unless it's a real lousy or poorly spec'd
motor. (Serious fan in any case...)

A 12A motor can draw well over three (or even five) times that much during
startup. 12V or more drop (assuming the previous math was right) at 100'.
That's a significant amount, and will significantly prolong startup and
produce more heat, and ultimately shorten the fan motor's lifetime. Perhaps
by not much, but perhaps by quite a bit.

This is a good place to go up a wire size. It's cheap.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.