PVRSS stands for Photo-Voltaic Rapid Shutdown System. This is the term used by UL (Underwriters Laboratories), the NEC (National Electrical Code) and NFPA (National Fire Protection Association) to designate the rapid shutdown methods, systems and equipment that are now required by NEC 690.12 and tested to
Until now, when a PV module is generating power, there has been no way to interrupt the flow from the junction box on the back of the module. SolarOff Systems, LLC has developed a low cost (typically less than $0.05 per watt) solution that can reliably perform this task. It is fail-safe, redundant, rugged and can be installed in most existing junction boxes. It can be used to shut down a single module or up to 100 in a string, an array or an entire system. Primarily for the Lifesafety of Firefighters and First Responders, it can also be used by Technicians and other service personal. Insurance companies will also have a keen interest, as in an active building fire the understandable thought to “let it burn” will no longer need to be a self-preservation consideration.
NEC 2014 requires that any PV system mounted on a building is required to include a method which will shut down all conductors (wires) to within 10’ of a module. Once initiated, the shutdown must reduce the voltage between any two conductors, or any conductor and ground, to less than 30 volts within 30 seconds. NEC 2017 is being developed to be further restrictive of the DC voltage on all conductors. The compliance date for PVRSS is set for January 2019.
The activation of a safety shutdown can be initiated by a manual means such as an electrical switch or disconnect, or automatically such as when the AC electrical service is turned off or disengaged from the grid.