What materials are typically used for electrical wiring insulation?

The correct answer is based on the properties and common applications of electrical insulation materials. PVC (polyvinyl chloride) and rubber are widely used for insulating electrical wires due to their excellent electrical insulating properties, durability, and resistance to moisture and environmental factors. These materials prevent electrical currents from escaping the wires, thus ensuring safety and efficiency in electrical systems.

PVC, in particular, is favored for its versatility, resistance to fire, and affordability, making it a common choice in both residential and industrial applications. Rubber provides flexibility, resilience, and strong insulating capabilities, which are essential in many electrical applications, especially where the wires may be exposed to movement or harsh conditions.

Other materials listed, such as aluminum and steel, are conductive and not suitable for insulation, while wood and plastic have limited application in electrical insulation compared to the robustness of PVC and rubber. Cotton and silk are outdated materials for insulation, as newer synthetic options like PVC and rubber provide improved performance and safety.