Anyone with 12v Air Conditioning Experience?
Having spent the better part of a week in a hot, dry and smokey campground that doesn't allow generators to run (I posted previously about this issue in another thread) it got me to thinking about som...
Forum Discussion
I think the Chinese codes are suspect. 8 ga AWG wire has 0.62 ohms/1000 ft. if of good quality. 18" of wire therefore has only 0.0009 ohms which doesn't sound like much. At 400A that is still only 0.37V drop which also doesn't sound like much. But it will dissipate 149 watts which sounds like one hellava lot! In fact it will do that for only a very short few seconds before the insulation melts and it is red hot. Wires are often sized for voltage drop, as apparently here, but there are also ampacity specs based on insulation temperature ratings, and #8 is typically 80 amps unless a very special high temp insulation - but never 400 amps!
So based on voltage drop of 3% - a typical metric for battery powered systems, #8 is fine because the run is so short, but based on ampacity you need at least 3/0, which is independent of run length.
So based on voltage drop of 3% - a typical metric for battery powered systems, #8 is fine because the run is so short, but based on ampacity you need at least 3/0, which is independent of run length.
