The National Electrical Code (NEC) requirements for solar PV system rapid shutdown were introduced in 2014, but if you haven't been keeping up since then, we're going to explain here how rapid shutdown for PV systems has evolved over the last six years.
In 2014, NEC requirement 690.12(1) through (5) was introduced to address rapid shutdown. It was short and sweet, with only six sentences:
PV system circuits installed on or in buildings shall include a rapid shutdown function that controls specific conductors in accordance with 690.12(1) through (5) as follows:
1. More than 5' inside a building, or more than 10' from a PV array.
2. Controlled conductors shall be limited to not more than 30V and 240 volt-amperes within 10 seconds of rapid shutdown initiation.
3. Voltage and power shall be measured between any two conductors and between any conductor and ground.
4. The rapid shutdown initiation methods shall be labeled in accordance with 690.56(B).
5. Equipment that performs the rapid shutdown shall be listed and identified.
These new requirements changed the game when it comes to solar PV system design. Different manufacturers started coming up with their own products and solutions to comply with rapid shutdown requirements. Then in 2017, the NEC amended 690.12, which led to more new solutions coming to market. NEC 2020 has brought yet more changes to rapid shutdown, and those six sentences from 2014 have grown into a full page.
To learn about all the changes to and solutions for the NEC 2020 rapid shutdown requirements, check out the full articles over at the altE blog: