Why is copper used in electrical wiring?
copper is a better conductor than gold.It's a common misconception that gold is better.It's most likely due to the fact that gold is the best HEAT conductor and that good heat conductors also tend to be good electric conductors.In electronics, gold is only used in applications that require the smallest wires.
Except for silver, copper is the best conductor.For normal use, silver is too expensive.
The aluminum is used for wiring.It is not as good a conductor as copper, so the wire diameter has to be larger to carry the same current.It's cost is competitive with copper.
The least resistance to current, save silver, makes copper a relatively inexpensive material for wiring.