What’s the Difference Between Module-Level Shutdown and String Inverters?

Module-Level Shutdown Basics

Module-level shutdown devices, also known as rapid shutdown devices, are designed to quickly disconnect power from individual solar panel modules in the event of an arc fault or grid fault. This helps to prevent electrical shock to utility workers or homeowners and reduces the risk of fires. Module-level shutdown devices must comply with UL 1741S and UL 2703 standards.

String Inverter Limitations

String inverters, which are still widely used in solar installations, can only shut down the entire string of solar panels if a fault is detected. This can result in significant downtime and loss of energy production, especially if multiple faults occur in the same string. In addition, string inverters may not always be able to detect faults immediately, leading to potential safety risks.

Choosing Module-Level Shutdown

When choosing a module-level shutdown solution, it’s essential to consider the specific requirements of your solar installation. For example, you may need to choose between a module-level shutdown device with a 10-second shutdown time or one with a 30-second shutdown time, depending on your local electrical codes and regulations. Additionally, you should select a device that is compatible with your existing solar panel and inverter setup.