Wire gauge for given load

Thanks; that puts me in good company and makes my "rule-of-thumb" official.

Did i or did i not say "following wire-size guide" followed with the guide? I cited no book or URL (did not exist 79 years ago). I made NO reference to wire ratings like those you refer to, or NEC or to other bushwah.

For one kiloamp or more?

You aren't paying attention, are you? Didn't think so.

ased on amps and length of wire.

city is limited by insulation temperature rating before wire gauge. If you go with some 300oC rated stuff, you can stuff a 100 A through 20ga. This is how you end up with wiring with small gauge inside an apparatus that is fu sed at 100A. It would not be practical to require humongous wire throughout or a bunch of different internal interrupters. Generally NEC wants the ins tallation to limit wire drop to less than 5% at nominal load, and there are three main insulation types in wide use rated at 60oC, 75oC and 90oC which have significantly different current ratings for the same gauge.

This is an awful lot of discussion for someone to buy a $3 extension cord, which is all he's after, one of the more ridiculous threads of all time.

ire-size

transformers in continuous use.

What the bleep is a circular mil? The circumference?

George H.

Wire is round. Cut the end off square and flush, and the face of that cut represents the area of one slice of the wire. Since wire is round, the area is described in "square millimeters" of course as that is how area is referred to in physical terms, but the term used is in describing the area within a circle is "circular mils". Since most wire is round, circular mils is a way of having a better grasp of how much copper a given wire size has.

te:

g wire-size

or transformers in continuous use.

Though I don't what a circular mil is, I'm pretty sure a mil is still 0.001" (inches)

GH Welcome back. :^)

It"s pi/4 of a square mil.

Cheers

Phil Hobbs

It's obvious! It's pi*.0005"^2. ;-) The area of a circle with a diameter of one mil.

A circular mil is the diameter of the wire (in mils) squared.

I am so poor, that i cannot afford to pay attention.

That explains a lot.