What type of metallic raceway is mounted to the surface or suspended from a structure for electrical conductors?

The choice of strut-type channel raceway is correct because this type of raceway is specifically designed for mounting on surfaces or suspending from structures to house electrical conductors. Strut channels typically possess a rectangular shape with a series of slots or holes that allow for the easy attachment of fittings and accessories, making them versatile for various installations.

Strut-type channel raceways are often used in industrial and commercial settings for supporting wiring and can accommodate changes in routing, expansion, and contraction. Their construction provides durability and a straightforward method for organizing and securing electrical conductors while maintaining accessibility for future modifications or inspections.

Other types of raceways mentioned, such as rigid conduit and flexible conduit, serve different purposes. Rigid conduit is designed for more permanent installations, primarily underground or in walls, while flexible conduit offers adaptability for systems requiring bending and movement. Utility raceway might refer to other non-specific types of raceway systems that do not necessarily match the specific mounting criteria as clearly as strut-type channel raceways do. Thus, strut-type channel raceway distinctly meets the criteria outlined in the question.