Several posts about electrical problems on the C3 reminded me of something that is good to know. Take a look at the photo below. This is the original ground wire between the chassis (near the rear end) and the battery negative terminal on my 1981 C3. Yes, it's Copper Clad Aluminum, or CCA, right from the factory. As we all know, aluminum is a good electrical conductor but not as good as plain old copper. The use of CCA, especially on high current draw circuits, can cause problems with several things. Especially if you are converting to a single wire alternator. The alternator has voltage sensing electronics inside of it. Small changes in the measured voltage at the alternator terminal is how the alternator knows to increase or reduce the output voltage. There can be enough resistance in the CCA to give a false reading to the alternator. I have found this to be a problem in several setups I've worked on.
Again, here is the factory original ground cable from my 81. I don't show it in the picture but the positive cable from the battery was also CCA.
And here is the all copper wire I replaced it with.
Be careful when buying wire from the auto supply stores, especially if the wire is made in China. Look for the letters CCA in very tiny print somewhere on the label. It is very common to find CCA wire at the auto supply stores. The stuff is crap. Personally, I buy all my wire from an online source that sells only made in USA wire. They also offer automotive wire with GXL insulation. It is thinner, tougher insulation that will withstand temperatures up to around 260°F without melting. Most of the auto supply wire has GPT (PVC) insulation that melts at around 175° and is nowhere near as tough.
CCA isn't great compared to copper, but it is still perfectly serviceable in correct situations. It's lighter weight than solid copper, and cheaper. When running lots of thicker gage wire this can make a big difference.
The issue in home fires was in cases where it was terminated to devices that weren't suitable for it, or when it was damaged in some way. It also would be undersized because a heavier gage was needed for a given amount of current when compared to solid copper. In the use as a battery cable in a car, the point where the wire terminates is already permanently attached from the factory. The wire is also able to correctly size correctly for the load it will handle at the factory. A smaller solid copper remote sense wire is also often used on alternators for the reason you listed above.
My point in saying this isn't to say that CCA is great, just that it isn't entirely terrible and isn't something that should immediately be replaced if you find one. I'd still agree that using solid copper when a replacement is needed is a great choice, and one that should strongly be considered if you aren't in a need to keep a budget or are looking to save every ounce of weight possible. I'd just also agree that the factory wasn't necessarily making a bad choice when they used it back then.
Aluminum is a very good heat conductor therefore at any connection it goes through heat cycles. Thus expanding and contracting. This over time loosens the connection causing more heat until the connection fails. In extreme cases the insulation gets hot and melts. This is where things go south in a bad way. When I wire any thing in a home I use only pure copper wire because life’s are at stake. Not to mention property or liability of me trying to save a few cents to boost my profit margins.