Which material is NOT typically used for electrical conductors?

Plastic is not typically used as a material for electrical conductors due to its insulating properties. Conductors are intended to facilitate the flow of electric current, and materials must have a high degree of conductivity. Copper and aluminum are widely used because they possess excellent conductivity, making them ideal for transmitting electricity efficiently. Steel can also be used in some applications, typically as a core material for structural stability, though its conductivity is lower than that of copper and aluminum.

In contrast, plastic serves as an insulator rather than a conductor. It prevents the flow of electricity and is often used to coat or encase conductors to protect against electrical faults and to provide safety for users. This insulating role is critical in electrical systems to avoid short circuits and ensure safe operation. Therefore, plastic does not fulfill the requirements to be considered a conductor of electricity, which makes it the correct choice in this context.