Code Change Summary: New exception added to provide relief from rapid shutdown requirements.

In the 2023 NEC^®, the new exception to 690.12(A) pertains to PV system circuits that originate within or from arrays that are not attached to buildings (such as a ground-mounted array) and terminate on the exterior of a building, and PV system circuits installed in accordance with Section 230.6. For these situations, the PV system circuits are not considered “controlled conductors” for the purposes of enforcing the rapid shutdown requirements in Section 690.12.

This code change was needed to provide clarity and help the code reader understand the intent of what the rapid shutdown requirements in 690.12 are there to accomplish.

The heading of Section 690.12 is “Rapid Shutdown of PV Systems on Buildings”. The opening statement immediately after the heading is “PV system circuits installed on or in buildings shall include a rapid shutdown function to reduce shock hazard for firefighters in accordance with 690.12(A) through (D).”

Technically, the way the section heading and opening statement are worded, without the new exception, the rules in 690.12(A) through (D) would apply, and rapid shutdown would be required for a building where PV system circuits coming from a ground-mounted array terminate at the exterior.

The purpose of rapid shutdown is to reduce shock hazards for firefighters employing rooftop operations on buildings where a potential shock hazard associated with rooftop PV arrays could exist.

The previous code language on conductors required to be controlled for the purpose of rapid shutdown applied to any PV system circuit that interfaced with a building, even if the actual array was 50 feet away on the ground.

PV system circuits from ground-mounted PV arrays or PV arrays mounted on parking lot shade structures are often routed to and terminated at a nearby building exterior wall where the inverter or other related electrical equipment is located. Requiring rapid shutdown for the actual building when PV system circuits never penetrate it is not what is intended in 690.12.

Below is a preview of the NEC^®. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2023 NEC^® edition of NFPA 70.