What is PV RSD?
Photovoltaic (PV) rapid shutdown devices are safety systems that can quickly shut down a solar panel system in an emergency. They are required by law for all new rooftop solar panel installations in the United States and are designed to protect firefighters and homes from fire.
Regulation in different countries
USA: National Electrical Code
The National Electrical Code (NEC) serves as the main regulatory standard for PV rapid shutdown devices in the U.S. It is revised every three years, with individual states adopting the updated regulations at their own pace.
NEC 2014
The NEC 2014 (Section 690.12) introduced clear guidelines for rapid shutdown in solar installations. It required the installation of a rapid shutdown switch for PV systems, ensuring that the system voltage drops below 30V within 10 seconds to enhance overall safety.
NEC 2017
In NEC 2017, the rapid shutdown requirements (Section 690.12) were made more stringent. It established a boundary of 305mm from the PV array, where, within 30 seconds of initiating shutdown, the voltage outside this boundary must drop below 30V, and within the boundary, the voltage should decrease to under 80V. This introduced the need for “Module-Level Rapid Shutdown,” significantly improving safety by reducing voltage to levels safe for human contact, thereby aiding firefighters in rescue situations.
NEC 2020
NEC 2020 introduced the concept of “PV hazard control systems.” The new standard requires PV systems to include this feature, ensuring that the system remains controllable in emergencies. Module-level rapid shutdown must be achieved, with voltage dropping below 80V within the boundary range within 30 seconds of shutdown activation.
NEC 2023
NEC 2023 requirements for rapid shutdown have not changed significantly from the 2020 version. As with NEC 2020, NEC 2023 Section 690.12(B)(2)(2) continues to state that within the boundaries of the PV array, the DC conductor must be controlled so that it does not exceed 80 volts for 30 seconds.
Canada: Canadian Electrical Code (CEC)
According to the Canadian Electrical Code 2021, an arc fault interrupter or equivalent is required when the DC side voltage of a PV system is greater than 80 V.In addition, the code requires that a rapid shutdown device be installed when the PV system is installed in or on a building. In addition, the code also stipulates that when the PV system is installed in or on a building, a rapid shutdown device should be installed. When triggered 1 meter away from the PV module, the rapid shutdown device is required to reduce the voltage to less than 30V within 30S.
Germany: VDE-AR-E 2100-712：2013
According to the VDE-AR-E 2100-712: 2013 standard, in the event of an inverter shutdown or grid fault, the DC voltage must be maintained below 120 V, with voltage regulation achieved through the use of a shutdown device.
Thailand: Thai Electrical Code
The Thai Electrical Code for Solar Rooftop Power Supply Installations 2022 specifies that a Rapid Shutdown Device (RSD) must be installed. This device is required to reduce the voltage to below 80V within 300mm of the PV array within 30 seconds of activation. For areas beyond this distance, the voltage must be reduced to below 30V within the same 30-second timeframe.
Philippine: Philippine Electrical Code 2017
The Philippine Electrical Code 2017 mandates that rooftop PV systems must incorporate a rapid shutdown function to ensure the safety of rooftop installations.
China
Anhui Province
Code for fire safety of PV system in buildings 4.3 pointed out that the building photovoltaic system fire prevention device requirements should be set up fast shutdown device
Beijing City
Specification of electrical safety for distributed photovoltaic power system requires that the system should be equipped with a fast shutdown function, and within 30s after the fast shutdown device is activated, the voltage within the boundary range should be reduced to less than 120v, and the voltage outside the boundary range should be reduced to less than 30v with the 305mm extension of the edge of the photovoltaic square array as the boundary.
Shengzheng City
Provide that PV modules shall have a safety shutdown protection function to ensure that the DC voltage in the system subarray is lower than the safety voltage (120V) after the inverter is shut down and the AC power is cut off.
Conclusion:
In the future, more countries will add fast shutdown to the mandatory standards, the global requirements for the safety of PV systems will be further improved, and fast shutdown technology may gradually become part of the standards of various countries.
