When may Class 1 circuit conductors and supply conductors occupy the same raceway?

Class 1 circuit conductors and supply conductors may occupy the same raceway when they are functionally associated. This means that the conductors share a common purpose or function within an electrical system. For example, if the supply conductors are used to power Class 1 devices, then their arrangement in the same raceway is justified since they work together in the operation of that equipment.

Occupying the same raceway helps streamline installation and maintains an organized layout of electrical systems, provided the conductors meet the necessary code requirements for protection and insulation. In practice, this can lead to improved efficiency and safety in the installation process.

While other options might seem plausible, they do not fully adhere to the definitions and requirements set forth by electrical codes regarding how and when these conductors can be run together. For instance, unassociated design does not imply any functional relationship; similarly, while insulation is crucial for safety, it alone does not justify the cohabitation of these conductors without their functional association. The idea of being "required by code" must align with established guidelines that specifically outline situations allowing shared raceway use, and functional association is a core consideration in these regulations.