Why isn't sodium used for overhead power cables?

Answer 1

The power cables are mostly built with aluminum and not with sodium because sodium is highly reactive. Aluminium on the other hand is reactive as well but it only reacts one and them becomes aluminum oxide. Sodium keeps on reacting therefore is too dangerous.

Answer 2

Although copper is a much more efficient conductor of electricity than steel, copper does not have the tensile strength that can be easily accomplished in various grades of steel. Steel can be economically produced in a wire form and then covered with aluminium or paired with aluminium conductors, and is often used in overhead cables for this reason; the combined steel and aluminium cables are strong due to the steel and conductive due to the aluminium and they are much more economical than making copper wire of the size and strength needed to use copper.

The supporting poles and structures would need to be much closer together and there would thus need to be more of them, in order to use the lower tensile strength copper as the overhead electricity conductor. That costs more money to get the electricity from point A to point B.

Overhead telephone lines using many small pairs of conductors are usually copper wire and often have a steel traveller cable paired with it to provide tensile strength.

Answer 3

Steel is not generally used because it is a relatively bad conductor of electricity. Copper is used in electrical circuits while aluminium, a slightly worse conductor but much lighter, is used in overhead power transmission. Brass is used in plugs and sockets because of its strength, and steel is also used in plugs for low-power equipment like radios and PCs.