Here's a way to remember wire resistance without having to refer to any tables, at least in the US where we use American Wire Gauge (AWG). It's plenty close enough for routine voltage drop calculations in small power systems or dB loss and damping factor calcs for speaker cables. Do this in your head and impress your friends.

The key: Remember that 10 AWG copper is 1 Ohm per 1000 ft.

10-1-1000, even I can remember that. (This is for 25 deg C and therefore a little lower than the number in the NEC tables, which are for elevated temperature, but who cares?)

Cross-sectional area of wire halves every three gauge numbers, so

R = 2^((AWG - 10) / 3)

where R is the resistance in Ohms per 1000 ft. and AWG is the gauge number. ("^" represents exponentiation so, for example, 2^3 = 8.)

If the difference between the gauge and 10 is a multiple of 3 you're done since the ratio of resistance is a power of 2. For example, 4 AWG is .25 Ohms per 1000 ft, 1 AWG is .125 Ohms per 1000 ft, etc.

If the gauge differs from 10 by other than a multiple of 3 you have to know your 1/3 octave bands. But, luckily, we're audio engineers. Just picture the front of a 1/3 octave graphic equalizer, which has bands at 1000, 1250, and 1600 Hz. These are the required ratios. So, for example, 8 AWG is 1 / 1.6 = .63 Ohms per 1000 ft. and 11 AWG is 1 * 1.25 = 1.25 Ohms per 1000 ft. (The actual ratios are closer to 1.26 and 1.59 but, again, close enough.)

To take the GEQ model a bit further, make 1000 Hz correspond to 10 AWG. Then just count off one band for each gauge number from 10 and the frequency divided by 1000 is the Ohms per 1000 ft.

Aluminum wire, for the same resistance as copper, is very close to 2 gauge numbers larger. So for aluminum just add 2 to the AWG and figure for copper.

[I posted something along these lines on the other forum a while back and it didn't get any traction. I try again here.]

--Frank