Code Change Summary: Revised PV system terminology resulting from the deletion of a PV Output Circuit.

In the 2023 NEC^®, the illustrations in Informational note Figure 690.1 were revised as a result of deleting the term “PV Output Circuit” from Article 690. In past editions of the NEC^® a PV Output Circuit was created when two or more series strings were connected in parallel. Now, this circuit will simply be incorporated into the revised definition of a PV Source Circuit in Article 100 to reduce confusing terminology. The intent is that it might be easier to understand them all as PV source circuits and determine conductor sizing based on their specified currents.

The proposal to delete the term was based on a public input from the PV Industry Forum (PVIF) who suggested that the definition of PV Output Circuit as compared to a PV Source Circuit has caused confusion among inspectors, installers, and system designers for years. The PVIF also stated that having a separate category for a PV Output Circuit lacks clear logic in regard to where source circuits end, and output circuits begin.

In the 2023 NEC^®, PV Source Circuits include the PV dc circuit conductors between PV modules in a PV string circuit, and from PV string circuits or dc combiners, to dc combiners, electronic power converters, or a dc PV system disconnecting means.

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.