What type of metal are typically in wires? I believe that usually wires are made out of copper. Are most wires made out of copper? Does the size of the wire usually determine what metal is in a wire? For instance, are larger wires typically composed of copper, while smaller wires are typically composed of iron? Is iron ever used in wires? Is steel ever used in wires? Is aluminum used in wires? I would like a general overview of the types of metal in wires.