"Paul" wrote in message
...
I'm confused by a couple of online calculators I've found.

I'm trying to determine the proper gauge wire to carry 20A, 120VAC over a
distance of 300 ft. with an approx allowable 2% (per NEC) voltage drop.
This UF cable will be buried for most of it's length.

This calculator:
http://www.stealth316.com/2-wire-resistance.htm
advises a 6 ga. wire would be sufficient (voltage drop 2.414V)

However, this calculator seems much more conservative:
http://www.vihon.com/Vihon_Calculato...alculator.html
It says a 0 (zero) gauge wire is required !

Use 600 feet and a maximum resistance of 0.12 Ohms ... and check out the
copper wire tables. Hope that helps.