Which of the following materials can be used as an equipment grounding conductor?

The use of both copper and aluminum as grounding conductors is aligned with National Electrical Code (NEC) standards and industry practices. Copper is commonly used for grounding because of its excellent conductivity, resistance to corrosion, and durability. It can effectively carry fault currents and provide a reliable path to ground.

Aluminum is also approved for use as a grounding conductor, offering a lighter weight and often lower cost alternative to copper. When properly sized, aluminum conductors can safely carry the same amount of current as their copper counterparts. However, it's important to ensure that aluminum grounding conductors are installed with specific care, such as using the correct connectors and considering thermal expansion and contraction properties.

Brass is not typically used as a grounding conductor because it does not provide the same level of conductivity and reliability in grounding applications compared to copper and aluminum. Additionally, while copper and aluminum are traditional materials that meet code requirements for grounding conductors, brass does not offer the same level of performance for this application. Therefore, the correct answer reflects the accepted materials for grounding conductors in electrical installations.