Solar and Rapid Shutdown Requirements
Previously, rapid shutdown was only used for each string of solar panels, and a string could consist of many panels wired in series.
The latest NEC 2017 code requires the ability for every individual panel to be shut off by a single switch, usually located in the front of a structure. This is so a fire person doesn’t have to squirt water on a live panel in the event of a fire.
In addition, a ground mount system is currently exempt from rapid shutdown requirements.
Some structures, such as garages or any area that is uninhabited, may also be exempt from rapid shutdown requirements.
SolarEdge and Enphase both comply with rapid shutdown requirements as their systems have rapid shutdown built in their optimizers and microinverters. Other inverters can utilize a electrical box behind each panel to accomplish rapid shutdown.
For more detailed information about rapid shutdown requirements, Energy Sage has a very informative overview of Rapid Shutdown Requirements.