Gee, I'm sorry. I thought the discussion WAS about wire gauge, which is what I was referring to, and it doesn't matter whether it is 5 volts, or 500 hundred volts to determine wire size, which tells you about how much current it can safely carry. As far as measuring the actual size using a micrometer to measure every strand on every wire is really not that necessary for automotive wire. It is either printed on the wire, or like you said, it's pretty easy to check with wire strippers. Multiple connections are a bigger concern usually. EVERY electrical problem simply comes down to Ohm's Law, from 1827, 192 years ago. I=E/R= AWG