PV module-level rapid shutdown (RSD) is a safety mechanism that is required by the National Electrical Code (NEC) for solar PV systems installed on buildings. The RSD system is designed to reduce electrical hazards in the event of an emergency shutoff or power outage. The RSD system works by rapidly shutting down the PV modules when an emergency condition is detected, such as a fire or other hazardous situation. This helps to prevent the risk of electric shock and fire, and allows emergency responders to safely work near the PV system. RSD is typically achieved with the use of special certified components and equipment that are installed with the PV modules. The Emergency Shutdown Switches offer a 24VDC power supply suitable for up to 480 panels opera -tion, with LED indicator to signal. Its compatible with all string inverters and does not affect their operation or perfor mance in any way。