"davidlaska" wrote in news:1157009586.378668.258860
@p79g2000cwp.googlegroups.com:

Phone company left me 500' of 4 strand telephone wire with a heavy
insulation that is rated tough enough where all you need to do is role
it out on the ground ( no burying or hanging or conduits needed). I
want to draw 12v dc at 0.2 amps (one fifth of a amp) over 200' and
want to calculate or know the voltage drop . I am guessing 30 AWG?


If it really is copper wire, then the following numbers might be helpful.

20 AWG, .032 in dia, 10.15 ohms per 1000 ft, 2 ohms per 200 ft., at 0.2
amp the voltage drop will be 0.4 volts each wire, total 0.8 volts for
two-wire setup. (If you parallel two wires out and two wires back,
making use of all 4 wires in the cable, total voltage drop is 0.4 volts.)

22 AWG .025 in dia, 16 ohms per 1000 ft. 3.2 ohms per 200 ft., total
voltage drop 1.2 volts (2 wire) or 0.6 volts (4 wire).

24 AWG .020 in dia, 25.7 ohms per 1000 ft, 5 ohms per 200 ft., total drop
2 volts (2-wire) or 1 volt (4-wire).

26 AWG .016 in dia, 41 ohms per 1000 ft, 8 ohms per 200 ft., total drop
3.2 volts (2-wire) or 1.6 volts (4-wire).

As you can see, you might get by with 20 or 22 AWG, but 26 AWG or smaller
is totally hopeless.

Wire data from http://www.powerstream.com/Wire_Size.htm