Code Change Summary: A new code section was added to address Rapid Shutdown equipment.

In the 2014 NEC^®, equipment performing the rapid shutdown was just required to be listed and identified. There was nothing requiring the products to be specifically listed for providing rapid shutdown protection. Technically, someone could install a listed push button initiation device that triggers a listed DC contactor on the roof within 10 feet from the array and run all of the DC source circuits through the listed DC contactor to satisfy the 2014 NEC^® rapid shutdown requirements.

In the 2017 NEC^®, the equipment that performs the rapid shutdown functions, other than initiation devices such as listed disconnect switches, circuit breakers, or control switches, shall be “listed for providing rapid shutdown protection”.

This new change makes it clear that the actual equipment responsible for shutting down the PV system circuits must be listed to the UL Standard that covers rapid shutdown. This does not apply to the rapid shutdown initiation device itself.

Requiring listing of the rapid shutdown equipment ensures failsafe measures are incorporated into the design. There is a general consensus that among other things, the rapid shutdown system should be failsafe since fire could damage the rapid shutdown system. Any loss of communication signals that allow the system to operate normally should also initiate the rapid shutdown.

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 2017 NEC^® edition of NFPA 70.