• Zeoic@lemmy.world
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      2 months ago

      How is aluminum non-conductive? It’s literally used as a lighter and cheaper alternative to copper in wires

      • KillingTimeItself@lemmy.dbzer0.com
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        2 months ago

        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.

        • Ilovethebomb@lemm.ee
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          2 months ago

          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.

          • KillingTimeItself@lemmy.dbzer0.com
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            2 months ago

            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.

        • Zeoic@lemmy.world
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          2 months ago

          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.