Rapid Shutdown is a safety feature required by the National Electric Code (NEC) for solar power systems. It is designed to ensure that in case of an emergency, such as a fire, the DC voltage of the solar panels is quickly and safely reduced to prevent electrical hazards. The rapid shutdown feature is implemented using switches or devices that are installed on the solar panels or on the roof where the panels are mounted. These switches can be manually or automatically activated, allowing for rapid shutdown of the solar power system.

The rapid shutdown feature is essential for ensuring the safety of firefighters and other emergency responders who may be called to a building with a solar power system. Without this feature, solar panels can continue to generate electricity even if the main power is turned off, posing a risk of electric shock or electrocution.

Rapid shutdown has become a standard requirement for solar power systems, and it is crucial to ensure that any system installed meets the NEC requirements for rapid shutdown.