Let’s say you have two wires: one is aluminum, the other is copper. Both are 100 feet long. Both are 0.01 Ω.
Yes, the aluminum wire would (obviously) have a larger cross-sectional area vs. the copper wire. But here’s what most people don’t know: The aluminum wire will be significantly lighter than the copper wire. That’s why the service wires going to your house are aluminum… if they were copper they would sag more, and the utility company would have to install more utility poles.
The weight advantage of aluminum (and copper clad aluminum) vs. copper is also why aircraft manufactures are very interested in it.
Yes, but we were talking about normal house circuits (‘branch wiring’, as mentioned in the It’s true that in specialized circumstances, aluminum wires are still used. Like service drops. Besides the weight, they have a couple of other special factors that allow aluminum wires here:
they are connected by professional electricians, into large, heavy terminals, and are seldom if ever disconnected.
they have less of the thermal expansion/contraction caused by turning circuits on/off in normal branch circuits. Most homes have some electricity being used all the time, so the service drop is always on.
But for the OP’s question, the likelihood of aluminum wiring making a comeback for branch wiring is very, very small, I think.
Unlikely. The wire you saw was tinned, not aluminum. That’s where they use copper wires with a tinned coating on the outside. All the benefits of copper with the added protection of oxidation/corrosion resistance.
The wires look like aluminum and may even feel like it but that’s due to their relatively small gauge and color (tinning makes the wires look like aluminum).
Late 60’s or early 70’s from my best estimates. I don’t think it was around all that long, maybe only a few years at most and not used everywhere, spotty.
One thing about aluminum that no one has mentioned is that its conductivity is less than that of copper. Thus, you had to use aluminum wire that was one size larger than copper wire for the same load (e.g., where 14 gauge copper is adequate, you have to use 12 gauge aluminum).
