This has got to be some kind of record! It was a full 8 hours 48
minutes before somebody gave the compulsory "You're an idiot for
asking a question like that - Hire a pro.". Mike asked a pretty
simple question. The closest you came to answering it was saying
that posting something (that wouldn't answer his question, BTW) can't
be done.

In article k.net,
says...
Mike Hartigan wrote:
Without consulting the code, it seems that everyone "just knows" that
14 gauge is used for 15 amps, 12 for 20 amps, etc. My question is -
how much margin of safety is there in this? I'm assuming that the
temperature of the wire at load was used to actually establish the
code. Presumably, though, 14 gauge could carry 16 amps without
creating a hazard. How about 17 amps? How about 18? ... (How many
hairs does it take to make a beard?). In a pinch, if you were
building something temporary - something you were going to tear down
in a week or two - would you use the 14 gauge you have on hand for
your table saw, or would you make a special trip to the store for 12?
At what point does the heat create an actual fire hazard? I'm not
considering over-fusing anything - I'm just curious. In Grandpa's
day, it was standard homeowner practice to simply insert a bigger
fuse when one kept blowing. No doubt the elders who wrote the
various versions of the code were aware of this practice and took it
into consideration when deciding on the numbers.

Mike
You don't need anyones permission to endanger yourself and your family.
If you are determined to ignore the code just do it. For my bread work
I'm an electrician. For my contribution to my community I'm a volunteer
firefighter. It's cheaper to use my services when I'm wearing my
firefighter's protective clothing but it's a lot safer to either learn
to do it safely yourself or higher me to do it for you.

It is true that when used in certain specific applications, with
specific loads, protected in specific ways, that number fourteen
American Wire Gage (AWG) copper conductors can carry more than fifteen
amperes.

I learned how to apply those uses during a four year apprenticeship
working with experienced electricians and going to school two nights a
week for those four years. Now you want me to spoon feed you the
ampacity rules, in toto, in a newsgroup posting. I'm sorry but that
cannot be done.
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous
for general use." Thomas Alva Edison