On Sat, 11 Aug 2007 20:42:10 +0000, Wes Stewart *n7ws*@ yahoo.com
wrote:

On Sat, 11 Aug 2007 12:41:38 GMT, Jim Behning
wrote:

|Speaking of useless answers. I went to some trade show years ago. I
|got a tote bag that might have said Copper is Proper. I cannot find
|the tote bag to see if that was the logo. Two points were made in the
|handout and it was geared towards commercial electricians. Well maybe
|one point. Copper flows electricity better than aluminum. 12 guage can
|be less expensive over the life of a building versus 14 guage due to
|lower power losses with the bigger wire. Equipment can run better with
|lower voltage drops.
|http://www.engineeringtoolbox.com/wi...ges-d_419.html
|http://www.jlmwholesale.com/images/WIREGAUGE.pdf
|
|Another anecdote which might be worthless. I have a friend who is
|certified in a lot of welding techniques. He has worked in power
|plants, oil rigs, made non destructive weld samples and seems to have
|a good bit of experience. He occasionally uses the small portable mig
|welder like I have in the garage. He has found that the little 120
|volt welder does better with 10 guage service wire than it does with
|12 guage service wire. I don't know how long the wire runs were when
|he was doing this experimenting but it reinforces the voltage drop.
|His eyes and skill with welds are better than my hack welds.


First of all, it's "gauge."

You don't need wire tables if you can remember that the resistance of
a round copper conductor is given by:

DC resistance ( Ohm/1000' at 20 C.) = 10 ^ (0.1 * AWG - 1)

where AWG is American Wire Gauge.

The resistivity of aluminum is approx 1.52 times copper.

So for a 20A run using 12 AWG, 100' long (200' of wire) the copper
loss is ~45 W.

For the same run in aluminum the loss is ~69 W.

The difference in efficiency (power delivered to load / power into
wire) is 98.1% vs. 97.1%.

Is this somthing to get excited about?
I am notorious for flipping letters around. Isn't dyslexia just a
wonderful thing?

Anyway it was not my argument.
http://www.copper.org/applications/e...onesizeup.html