What type of line must be used in the diagram to indicate areas that remain energized after rapid shutdown?

In the context of the NEC Article 690, indicating areas that remain energized after rapid shutdown is crucial for ensuring safety and awareness during maintenance or servicing of solar photovoltaic (PV) systems. The use of a dotted line in diagrams serves a specific purpose: it visually distinguishes areas that have different electrical characteristics than those that are fully de-energized during the rapid shutdown process.

This representation helps personnel easily identify which parts of the system may still carry voltage and thus require caution even after a shutdown is initiated. It enhances clarity in documentation and communication about the system's safety features. Utilizing a dotted line effectively conveys the message that certain areas are still live, while not overwhelming the diagram with solid lines that indicate continuously energized circuits.

In contrast, the other types of lines, such as solid lines and dashed lines, may imply continuous operation or different conditions that do not effectively communicate the specific nuance of post-shutdown energization. Therefore, the choice of a dotted line is standardized for this purpose, ensuring that anyone reviewing the diagram can quickly recognize the associated safety concerns.