Quick Answer
Rapid shutdown is a critical safety feature that disconnects the DC power from solar panels to the inverter in the event of an emergency, and it must comply with NEC 2014 690.12, which requires that the disconnect be within 10 seconds of the emergency shutdown signal.
Understanding Rapid Shutdown
Rapid shutdown is a safety requirement for solar panel systems that ensures the DC power is disconnected within 10 seconds of an emergency shutdown signal. This is typically achieved by a DC disconnect device that is installed between the solar panels and the inverter. The DC disconnect device must be a dedicated device, and not a regular breaker or switch, to ensure safe operation.
Compliant Solutions
Several manufacturers offer compliant rapid shutdown solutions that meet the NEC 2014 690.12 requirements. These solutions typically include a DC disconnect device that can be installed in the field and a compatible inverter that can send the emergency shutdown signal. One example of a compliant solution is the use of a DC disconnect device with a 10-second time delay, such as the SolaHD DC Disconnect, which can be installed in series with the solar panels and the inverter. This device must be installed within 10 inches of the inverter and must be easily accessible.
Installation Considerations
When installing a rapid shutdown system, it’s essential to consider the location of the DC disconnect device and the emergency shutdown signal. The DC disconnect device must be installed within 10 inches of the inverter and must be easily accessible for maintenance and testing. Additionally, the emergency shutdown signal must be sent to the DC disconnect device within 10 seconds of an emergency shutdown signal being sent to the inverter.
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