# Rapid Shutdown

A safety requirement that the DC conductors of a rooftop PV array be brought down to a low, touch-safe voltage quickly once an initiator is operated, so firefighters and maintenance staff can work on the roof. It is enforced by module-level or string-level shutdown devices.

Source: https://inverterdata.com/en/glossary/rapid-shutdown/
Site: InverterData (inverterdata.com) — open technical specification database
Last updated: 2026-08-24
License: free to quote with attribution to inverterdata.com

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In the United States the National Electrical Code requires conductors inside the array boundary to fall to 80 V or less within 30 seconds of initiation, with a different limit for conductors outside it. Compliance is achieved with microinverters, power optimisers, or dedicated rapid shutdown switches paired with a compatible inverter. Requirements vary by jurisdiction, so the applicable rule depends on where the system is installed. Even after shutdown the modules themselves still generate their own voltage internally — the requirement limits what is present on the wiring, not what the cells produce.