Rapid Shutdown

Rapid shutdown is a safety requirement mandated by the National Electrical Code (NEC) that ensures rooftop solar systems can quickly reduce voltage to safe levels in an emergency. This protects firefighters, utility workers, and first responders from the risk of electrical shock when accessing a roof with solar panels.

Since 2017, the NEC (Section 690.12) has required that conductors within the array boundary be reduced to 80 volts or less within 30 seconds of activating the rapid shutdown. This means each panel must have a module-level device — either a microinverter, a power optimizer with rapid shutdown capability, or a dedicated rapid shutdown device — that de-energizes the panel on command. The shutdown is typically initiated by turning off the inverter or activating a dedicated rapid shutdown switch. This US-specific requirement has made module-level power electronics (MLPE) effectively standard on most new residential installations. Older systems installed before the requirement may not have rapid shutdown capability. If you’re getting a new system installed, rapid shutdown compliance is handled automatically by your installer’s equipment choices.