Which option is permitted as the common grounding electrode conductor for separately derived systems?

The correct choice indicates that any type of conductor—copper, aluminum, or plated—can be used as the common grounding electrode conductor for separately derived systems. This flexibility is essential for electrical installations, particularly for systems that are electrically isolated from the primary power supply.

Different materials can be used depending on various factors such as cost, availability, and specific project requirements. Copper is known for its excellent conductivity and resistance to corrosion, making it a popular choice. Aluminum, while having slightly lower conductivity, is lighter and often more cost-effective. Plated conductors, which typically involve a layer of a more conductive or corrosion-resistant material bonded to a base material, can also provide good performance for grounding applications.

Using any of these materials as a grounding electrode conductor allows for a variety of design approaches while still ensuring safety and compliance with electrical standards. This adaptability is particularly beneficial in ensuring that installations can meet specific environmental needs and budget constraints.