I'm trying to understand when Rapid Shutdown (RSD) is required for solar installations. Some local inspectors say it's necessary, while others claim it's not needed for nearly the same installation type. Can anyone clarify when an RSD is actually needed, especially for roof-mounted vs. ground-mounted systems?
3 Answers
In most areas, you will need RSD for any roof-mounted array. If you're using microinverters, those usually provide their own rapid shutdown function as well, so you might not need an additional system if that's the case.
It usually depends on the local codes where you live. Generally, any roof-mounted solar system will require rapid shutdown functionality. If you're dealing with ground-mounted systems, though, you typically don't have to worry about RSD. You might want to check with your local regulations to be sure!
The NEC (National Electric Code) specifies that PV system circuits on or in buildings must have rapid shutdown capabilities. This includes both residential and commercial setups. However, ground-mounted setups don’t count as buildings, so they don’t need RSD. Also, the requirements can vary depending on what code cycle your Authority Having Jurisdiction (AHJ) is on, and it's possible for them to waive certain requirements, although that might be unusual. Essentially, it all boils down to your local AHJ's rules!
I've heard that in areas with steep roofs, inspectors might be more lenient and waive the RSD if the roof isn't traversable. Maybe that applies here?
That makes sense but it confuses me too. We’re on the latest 2020 code and an inspector told me we didn’t need RSD, but I planned on installing it just in case.