On Tuesday, July 16, 2019 at 5:36:33 AM UTC-5, kinsell wrote:
On 7/15/19 9:04 PM, Charlie M. (UH & 002 owner/pilot) wrote:

Fuses and breakers are really to protect the wire from overloads.
A 12ga wire is good for a max load of about 20A. We won't get into free air load vs. in a bundle or conduit (it is rated at less).
Sooo.....a 12ga wire can carry about 20A load.

No, it can carry a whole lot more than that. Residential electrical
codes limit it to 20 amps to minimize I*R drops, where the length of the
wiring could reach into hundreds of feet. The wiring will actually
handle over 200 amps before it starts to melt.

Not to be pedantic but ... FAA Advisory Circular AC43-13-1B defines the maximum current along 20ft of 12ga mil-spec (Tefzel) wire across 14Vdc as ~12amps (fig 11-2 continuous current flow) or ~22 amps (fig 11-3 intermittent current flow).

Reminder that this is DC, not AC, current we are talking about. Edison pushed DC systems but was beat out (trounced) by Tesla/Westinghouse and their long-haul AC systems due to exactly what we are talking about here. Just sayin'. ;-)

Thanks, John

References:
https://en.wikipedia.org/wiki/War_of_the_currents
https://www.faa.gov/documentLibrary/...-1B_w-chg1.pdf