The problem with aluminum for conduction is that (1) it does not like to be clamped down (it tends to back away from the screw terminals so you will have to re-tighten them or use a different clamping mechanism) and (2) it tends to oxidize so even a slight loss of contact will turn into a much higher resistance on the joint.<p>Copper doesn&#x27;t have these draw-backs which is why it is used a lot more on the &#x27;low power&#x27; side of things.<p>But for the transmission lines the reduced weight more than offsets all the other issues, those are very well taken care of connections with resistances in the milli-Ohms, an expensive connector is not an issue when it comes to power infrastructure.