Rapid Shutdown Device
Equipment that quickly reduces solar panel voltage to safe levels (under 80V within 30 seconds) when the system is shut off, as required by NEC 2017+ section 690.12.
Why It Matters
Rapid shutdown protects firefighters who may need to work on a roof with solar panels. Microinverters and power optimizers inherently provide this function.
Related Terms
Rapid Shutdown
An NEC (National Electrical Code) safety requirement that solar systems must be able to reduce rooftop DC voltage to safe levels within 30 seconds of initiating shutdown, protecting firefighters and first responders.
NEC (National Electrical Code)
The U.S. standard for electrical installation safety (NFPA 70). Article 690 specifically covers solar PV systems, including wiring, grounding, labeling, and rapid shutdown requirements.
Power Optimizer
A DC-to-DC converter installed behind each solar panel that maximizes the output of individual panels before sending power to a central string inverter.
Microinverter
A small inverter attached to each solar panel, allowing independent operation and optimization of each panel.