Section 408.4(B) of the National Electrical Code (NEC) requires circuit directory or circuit identification to "clearly indicate its purpose or use."The key to understanding whether 408.4(B) requires source labeling (i.e., identifying the panel that feeds the loadcenter) in a high-rise residential application is the interpretation of "purpose or use."Here's the analysis



NEC 408.4(A) states

"All circuits shall be legibly identified as to their clear, evident, and specific purpose or use."

Source labeling is not explicitly required by NEC 408.4(B). The NEC doesn't directly say "identify the source panel." However, indirectly it may be required. Consider this: If the loadcenter is fed from a different panel on a different floor, and tracing the circuit back is difficult or impossible without documentation, then the purpose or use of the circuit might arguably require identifying the source panel. Local AHJ (Authority Having Jurisdiction) Interpretation

This is the most important factor. Some AHJs will interpret "purpose or use" to mean that source identification is essential, especially in high-rise buildings, for troubleshooting, maintenance, and emergency situations. Others might not.

Always consult with the local AHJ for their specific requirements. Good Practice and Safety

Even if not strictly required, labeling the source panel is a very good practice. It makes troubleshooting much easier, reduces the risk of working on the wrong circuit, and can significantly improve safety.

In summary

The NEC does not explicitly mandate source labeling of loadcenters within a dwelling unit served from a remote panel in a high-rise. However, it is highly recommended, and the local AHJ might require it based on their interpretation of "purpose or use." Always check with the local AHJ for their interpretation and requirements. When in doubt, err on the side of safety and clarity by including source labeling.Therefore, the answer is

"It depends on the local AHJ interpretation. While not explicitly required by the NEC, many AHJs may require it. Always check with the local AHJ." Flag for review