What is the requirement for conductors 8 AWG and larger when installed in raceways if not explicitly permitted to be solid?

For conductors that are 8 AWG and larger when installed in raceways, the requirement is that they must be stranded unless explicitly permitted to be solid. Stranded conductors comprise multiple smaller wires twisted together, which provides increased flexibility and ease of installation, especially in tight spaces or when making connections. This is crucial in preventing the conductor from experiencing damage due to movement or vibration over time, which can lead to increased risk of failure.

In contrast, solid conductors, while they may have advantages in some applications, can be less flexible and more prone to breaking when subjected to bending or flexing, particularly in environments where the conductor might be moved frequently. Hence, the specification for stranded conductors helps ensure reliability and safety in installations involving larger gauge wires in raceways.