2023 NEC Article 706.15 – Clarifying ESS Emergency Shutdown

In 2022, the National Fire Protection Administration (NFPA) released the 2023 National Electrical Code (NEC). Updating the code every 3 years allows for clarification and correction of unintended consequences or gaps in the regulations. Article 706.15 in the 2023 NEC is a great example of why it’s important to continually update the NEC. Tune into this excerpt from Sean White and Bill Brooks’ webinar – 2023 National Electrical Code Updates for the Solar Industry – to learn more about emergency shutdown for energy storage systems (ESS).

This is a really significant change in the code. It’s probably what I would consider one of the biggest changes that we got in the 2023 code – to clarify the emergency shutdown idea for article 706. 

For one and two family dwellings, it was required for a disconnect to be outside the house. And a lot of jurisdictions were requiring load break switches and things like that, which could be very problematic on a lot of systems. That was really not the intent.

The intent was to shut down the system very similar to rapid shutdown. And so we’re seeing some of these concepts of rapid shutdown and emergency shutdown converge. 

The reason we use the term rapid shutdown in article 690 is because the correlating committee that runs the code said we couldn’t use the word emergency. Because that’s the way we had originally termed it. So we said, fine. We were kind and we came back with a term that everybody hated, which was rapid shutdown – and everybody disliked that. Maybe we’ll get rid of it someday. 

Then along came [article] 706. They didn’t slap 706 Code Making Panel 13 on the hand when they came up with the idea of emergency shutdown.

It actually stuck. At least, it’s in the code for now. That emergency shutdown is now called a function, like rapid shutdown function, using very similar language we did in rapid shutdown. Now we can cease to energize or export power, rather than have an actual load break switch.

For instance, there’s little switches on almost every energy storage system. That little switch that’s on the side of it could be wired through just a push button or something like that, just a relay that would activate that and take it offline. That can be done much more inexpensively, easier to wire, simpler. 

It also provides information on what was intended in the 2020 code. Most people on the call probably are still on the 2020 code. If you’re on the 2020 code, it’s not clear what would be acceptable. 

The 2023 code actually provides an additional level of clarity that,  if I were working on the 2020 code with a jurisdiction, I would use this information as clarifying what was actually meant by the unclear statements in the 2020 code. So that’s good enough.