Quick Answer
A dedicated DC disconnect switch is required for solar installations with inverters that have an integrated DC disconnect, or for installations with more than one inverter or string. This requirement may vary depending on local electrical codes and regulations.
NEC Requirements
The National Electric Code (NEC) requires a dedicated DC disconnect switch to be installed between the DC source (solar panels) and the inverter. This is typically referred to as a “DC disconnect” or “DC safety switch.” The DC disconnect switch must be rated for the maximum DC voltage and current of the solar array, and must be easily accessible for maintenance and inspection.
Inverter Requirements
Most modern solar inverters have an integrated DC disconnect switch, but some may require a separate DC disconnect switch to be installed. For example, string inverters typically require a separate DC disconnect switch for each string, while microinverters may not require a separate DC disconnect switch. Inverters with integrated DC disconnects still require a separate disconnect on the AC side, but the DC disconnect is typically built into the inverter itself.
Best Practices
To ensure safe and efficient solar operation, it’s recommended to install a dedicated DC disconnect switch even when not required by local codes. This provides an additional layer of safety and makes it easier to troubleshoot and maintain the solar array. The DC disconnect switch should be rated for the maximum DC voltage and current of the solar array, and should be installed in a location that is easily accessible for maintenance and inspection.
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