Why are power cables made from iron and aluminium?

Answer 1

#1

Primarily because of its lighter weight. Copper is a better conductor, but is too heavy and more expensive.

#2

Aluminium is lighter than most other metals yet still strong enough to carry its weight, so the cables do not need to be monstrously thick, and it is a fairly highly conductive material (being a metal) so power is not wasted on the transmission. It should be noted, however, that aluminum by itself is not normally used for long spans, i.e. high-voltage power transmission. It is wrapped around a steel core. The steel is used for strength, and the aluminum is used for better conductivity. Such cable is called type ACSR (short for aluminum conductor - steel reinforced).

#3

Because of its light weight. It is great at conducting a current and copper is expensive.

#4

Because of conductivity.

Answer 2

Iron is a relatively poor conductor with just 14% of the conductivity (how well it conducts) of silver, which is the best metal conductor. The conductivity of copper, on the other hand, is 95% that of silver, and aluminium is 58%.

So iron is NOT used in the manufacture of power cables, but copper and aluminium (being relatively cheap and plentiful) are.

Answer 3

Cost of aluminum vs. copper and weight (which means the poles don't have to be as strong, again resulting in lower cost).

Answer 4

Because it is an excellent conductor of electricity and its light :)