Which of the following items is NOT defined as a raceway?

The auxiliary gutter is an important component in electrical installations, often used to house and manage cables. However, it is not categorized as a raceway according to the National Electrical Code (NEC). A raceway is a specific pathway designed for the housing of conductors, which includes items like conduit and cable trays. Although auxiliary gutters can contain conductors, they do not fit the strict definition of a raceway because they are more akin to a distribution system for electrical wiring rather than a protective conduit through which conductors travel.

In contrast, cellular concrete floor raceways, electrical non-metallic tubing, and rigid non-metallic conduit all serve the function of providing a protective pathway for electrical conductors, which firmly places them within the definition of raceways. Understanding these distinctions is crucial for compliance with electrical codes and ensuring safe electrical installations.