Rapid Shutdown

Rapid shutdown equipment lets firefighters and service crews quickly de-energize the PV conductors on a roof. NEC 690.12 requires rapid shutdown for PV systems on buildings, and most string-inverter arrays meet it with a device at each module plus a transmitter or initiator that keeps those devices on during normal operation. This collection groups our rapid shutdown devices, transmitters, and initiator switches by system so you can complete the whole bill of materials.

Read more about Rapid Shutdown

Best for

  • String-inverter rooftop arrays that need module-level rapid shutdown
  • Installers completing a Tigo, APsmart, or Tesla rapid shutdown parts list
  • Replacing or adding rapid shutdown units on an existing array

Shop by system

Tigo Fire Safety. Use the Tigo TS4-A-F (one per module) or the Tigo TS4-A-2F. They are held on by a Tigo RSS Transmitter or by a UL PVRSS-certified inverter with a built-in Tigo transmitter. The Tigo Cloud Connect Advanced outdoor kit adds data logging and rapid shutdown control.

APsmart (SunSpec PLC). The APsmart RSD-S-PLC-415 module unit pairs with the APsmart Transmitter PLC Outdoor Kit (408006) or a compatible inverter with an integrated SunSpec transmitter. The APsmart BG10P34-11 initiator switch gives you an emergency button that cuts power to the transmitter.

Tesla. The Tesla MCI-2 15A mid-circuit interrupter is for Tesla Solar Inverter and Powerwall PV arrays. Shutdown is triggered when AC to the Tesla system is lost.

Enphase microinverters. Enphase IQ microinverter systems are designed to handle rapid shutdown at the module, so they usually don't need add-on rapid shutdown units. Browse microinverters.

Important considerations

  • Module devices and transmitters must use the same signaling system. Check the manufacturer's compatibility list before mixing brands.
  • Many inverters include a built-in transmitter, which can replace a standalone one. Check your inverter's datasheet.
  • Match each device's current and voltage limits to your modules and strings. Limits are on each product page and the manufacturer datasheet.
  • Your local inspector (AHJ) and the code edition adopted in your area decide which rapid shutdown method is accepted.

Rapid shutdown FAQ

Does the Tigo TS4-A-F need a transmitter?

Yes. The TS4-A-F does not work alone. It needs a Tigo RSS Transmitter or a UL PVRSS-certified inverter with an integrated Tigo RSS transmitter.

How is rapid shutdown started?

In keep-alive systems such as Tigo and APsmart, removing power from the transmitter, for example with an initiator switch or by turning off AC, stops the signal and the module devices shut down. Tesla MCI devices shut down when AC to the Tesla system is lost.

Do Enphase microinverters need separate rapid shutdown devices?

Usually not, because Enphase IQ microinverters are designed to meet rapid shutdown at the module. Confirm with the Enphase documentation and your inspector for your specific system.

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