How should branch circuits be identified if they are supplied from multiple voltage systems?

Branch circuits supplied from multiple voltage systems must be identified by phase or line and by nominal voltage system to ensure safety and clarity during electrical work. This practice is crucial because it provides essential information about how the circuits are supplied, allowing electricians and technicians to understand which circuits operate at which voltages and phases.

By identifying circuits in this manner, it minimizes the risk of confusion when working on or troubleshooting these circuits. Electricians can quickly determine the correct voltage and phase they are dealing with, which is essential for maintaining safety protocols and preventing electrical accidents that could arise from incorrect assumptions regarding circuit configurations.

When circuits are merely labeled by circuit number, color coding, or location, there can be ambiguity or misinterpretation, especially in complex systems with similar configurations. Using phase or line designation coupled with nominal voltage provides the most comprehensive and safe identification method.