"Jim Adney" wrote in message
...

....
| I suspect that for long distance transmission lines the stranding is
| often a mix of plated steel on the inside for strength and copper on
| the outside for conductivity. The skin depth makes that a reasonable
| choice.
....

Aluminium is often the choice. Also I heard once that some cables use a low
Curie point coating which increases in resistance and heat loss below a
certain point melting off any ice build up.

N