this post was submitted on 10 Sep 2024
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Was about to say
How is aluminum non-conductive? It's literally used as a lighter and cheaper alternative to copper in wires
to my knowledge, the only place they use aluminum as a conductor is in overhead external transmission lines, because you can wrap them around a steel or fiberglass/carbon fiber core (due to the skin effect this incurs minimal losses) while increasing strength and reducing weight (with the composites at least)
the secondary reason is because you can just use more aluminum, since it's not nearly as dense as copper, and also allows you to string farther, since again, not nearly as dense.
most aluminum wiring is actually cladded in copper, it's called CCA for what should be fairly obvious reasons.
Also i believe the oxide coating of aluminum isn't conductive? The bare material itself is, but once it oxidizes it's probably not a good conductor, this is why we use shit like gold plated contacts. Copper also oxidizes as well, but it's not nearly as bad.
Aluminium is a better conductor than copper by weight, but not cross sectional area. It's used in aerial conductors because the weight is more important than the diameter. And it's cheaper.
it's technically like four different reasons.
The big one is weight per foot of current carrying capacity. this reduces the amount of transmission towers you need, reducing the amount of labor, and raw materials. the aluminum itself is cheaper, but that's a secondary effect. Since it's not as heavy per unit, you can make the runs much cheaper. And since you can make them cheaper, you can carry more current by simply making them bigger, or adding more of them.
compounding effects are something funky.
CCA Ethernet cables are literally the worst. The wires are much more brittle so it's much easier to break the cable just by bending it a little bit, and since the resistance is significantly higher, they can't go as far as regular pure copper cables, and you can't use them for Power over Ethernet (they'll overheat).
People buy them to save money since they can be a lot cheaper, but often end up having to re-run a lot of the cables in the future. Better to just buy the high quality cables from the beginning. "Buy once, cry once" as the saying goes.
yeah, this is a pretty common issue with CCA cabling, normally this is why people go for things like OFC wire instead, it also carries a little bit more current which is nice.
Sure, aluminum as the sole conductor is rare, but as you said, there is CCA, which is ridiculously common. CCA is mostly aluminum to save cost but is still 60ish% as conductive as copper.