What materials are commonly used for electrical conduit?

The correct choice highlights materials that are well-established and widely used in electrical conduit applications. PVC, or polyvinyl chloride, is a popular choice for non-metallic conduit due to its resistance to moisture and corrosion, making it suitable for interior and exterior installations. EMT, or electrical metallic tubing, offers a lightweight, durable metal option that provides good protection for conductors, often used in commercial and industrial settings. Flexible metal conduit is utilized where flexibility is required, allowing for easier installation in tight spaces or areas requiring motion.

In contrast, the inclusion of wood or solely plastic materials in conduit systems is not appropriate, as wood does not provide the necessary fire resistance or electrical protection required for conduits. Glass and ceramic are also unsuitable; they do not have the mechanical strength or appropriate properties for safely routing electrical conductors. Hence, the chosen answer accurately represents the standard materials utilized in electrical conduit systems, aligning with industry standards and practices.