What is the suitable method of identifying conductors of a multiwire branch circuit when multiple nominal voltage systems exist?

Using color-coding is the suitable method for identifying conductors of a multiwire branch circuit, particularly when multiple nominal voltage systems exist. Color-coding provides a clear and standardized visual reference that helps ensure safety and prevents confusion among conductors of different voltage levels. This method allows electricians and anyone working on electrical systems to quickly and easily identify the intended use and voltage of each conductor, significantly reducing the risk of errors during installation or maintenance.

Color-coding adheres to standards set forth by the National Electrical Code (NEC) and industry practice, which dictate specific colors for different types of conductors. This system not only enhances safety but also promotes consistency in electrical installations, making it easier for professionals to work with existing systems.

While other methods like tape measures, tags, or marker pens can be useful in certain contexts, they lack the immediate clarity and standardization provided by color-coding. Tape measures do not provide visual identification, tags might be misplaced or removed, and marker pens can fade or be illegible over time. Thus, color-coding remains the most effective and recognized strategy for conductor identification in complex multi-voltage setups.