4 ms·
According to (http://www.faqs.org/faqs/electrical-wiring/part1/section-20.html http://www.faqs.org/faqs/electrical-wiring/part1/section-20....) and to the wiki
by ramchip 16y ago
According to (http://www.faqs.org/faqs/electrical-wiring/part1/section-20.html http://www.faqs.org/faqs/electrical-wiring/part1/section-20....) and to the wiki article on wire gauges, 40A requires 8-gauge wire, which is 3.264mm in diameter, while 20A is 12-gauge, which is 2.054mm. The ratio of their cross-sectional area is 2.53; this justifies that the 40A wire conducts twice as much as the 20A but has 2.53 as much area, thus being more costly.
I'm not sure why. Is the skin effect sufficient to explain this?
- mturmon 16y agoSkin effect is not a factor in 12AWG wire at 60Hz. It takes much higher gauges and/or higher frequencies.
- regularfry 16y agoI doubt it's skin effect. More likely to be a safety margin so that it doesn't risk overheating.