do i understand how power works in our cars?

[ncc74656]

I would like to ask this question as a thought experiment to determine if I am properly understanding the following relationships with wiring and power.

Our speakers get AC out of our amps and our amps get DC from our power system. The DC power does not have frequency as it is a single flowing direct current and as such the flow of electrons through any wire have ZERO skin effect as skin effect is only applicable with frequency of transmission. What does play a part in power capacity however is the material of which the wiring is made of and how it is made. The total measured DC resistance of a cable of X size will be lower in copper material than it will be with aluminum. Also the resistance of said wire (given that it is the exact same diameter) will be lower with a single solid strand than with a multi stranded wire.
Wire used in AC systems such as our speakers will gain resistance with frequency and will also increase its skin effect with frequency. Our subs normally operate from 20-120hz (in most installs) and thus the skin effect of signals even up to 150hz leaves a skin depth of .244" useable on the cable. this means that in a 1" diameter cable that only 1/4 of it would be useable for current transfer. Given that most of us (myself included) use only up to 8GA wire (for amp to speaker) and given that 8ga wire is .1285" in diameter that there is no conceivable way that skin effect will play any part in the transmission of power through this wire. one would need to be at 550hz or greater to the sub before the very center of this 8ga wire would no longer be used. In mid range and tweeter applications we use much smaller wire say perhaps 16ga for mids and 24ga for tweeters. this puts the skin effect at 118% the diameter of a 16ga wire for the mids and 102% for the tweeters. in this scenario there is no way that I can envision skin effect will have any bearing on the power requirements for signal transmission in car audio.

Now in power wires we have CCA and OFC, CCA being aluminum wrapped with copper and OFC being supposedly 99.9% or greater free of oxygen and being pure copper in construction. If one were dealing with high frequency AC current the CCA or even CCS would not matter as the copper on the outside would be the only part of the wire to see electron flow however in our car audio application it is the thermal inductance that factors into the CCA wire. meaning that the CCA wire is 25% less conductive than the copper wire due to aluminum having ~25% less conductivity than copper and a greater propensity for capacitance. thus given 2 runs of identical gauge wire but one being CCA and one being OFC and both having 80% of rated AWG power handling capacity the CCA wire will reach a temperature considerably higher than the OFC and thus will have a greater resistance to the flow of electrons and deliver less power to the amp with a greater demand on the electrical system.

[sundown escort]

To my understanding, you are correct. I believe that some CCA with be considerably less conductive based on the brand though ie. less copper. Also, I believe that using CCA for AC current would yield more power loss than just the power loss from thermal inductance. I say this because the factor of skin effect, each strand is copper coated. If it was completely aluminum in the center and completely copper on the outside(like a copper pipe full of aluminum), what you are saying would make more sense, to me at least. I am not an expert by any means, so take it for what its worth.