Code Change Summary: A new exception was added to 690.8(B)(1) to harmonize PV conductor ampacity rules with similar allowances elsewhere in the NEC^®.

SME commentary: Section 690.8(B)(1) in the 2026 NEC^® includes a new second exception that aligns the ampacity rules for PV circuit conductors with the allowances already found in Sections 210.19(A)(1), 215.4(A)(1), and 705.28(B). The base requirement in 690.8(B)(1) remains unchanged. PV circuit conductors that are sized without including any adjustment and correction factors must still have an ampacity not less than the maximum currents calculated in 690.8(A), multiplied by 125 percent. This has been the long-accepted requirement for PV source circuits and output circuits when using the straightforward 125 percent method found in 690.8(A)(1)(a)(1).

Historically, the only relief available in this subsection was an exception that allowed circuits containing an assembly listed for continuous operation at 100 percent of its rating to be used at that rating. This aligned with similar 100 percent rated allowances in other parts of the NEC^®. However, PV systems have evolved, and installations today commonly incorporate separately installed pressure connectors, especially in systems that route conductors through combiner enclosures, gutters, and auxiliary junction points rather than terminating directly on module-level electronics or inverters. The Code-Making Panel agreed that the PV industry would benefit from an ampacity allowance consistent with the pressure-connector exceptions already established for branch circuits, feeders, and interconnected power production sources.

In the 2026 NEC^®, new Exception No. 2 under 690.8(B)(1) permits a portion of a PV circuit to be sized based on the calculated maximum current of 690.8(A), without requiring an additional 125 percent multiplier, provided that both the supply and load ends of that portion terminate on separately installed pressure connectors rated in accordance with 110.14(C)(2). This matches the logic applied in the branch-circuit and feeder exceptions, which recognize that a segment of conductor between two higher-temperature-rated connections does not have the same terminal temperature limitations as the ends that land on the equipment. This exception is particularly useful for PV system configurations where temperature-rated pressure connectors are installed in intermediate enclosures before the final connection to the inverter or other equipment.

To maintain consistency with other applications of this rule, the exception also includes the familiar limitation that “no portion of the circuit installed under this exception shall extend into an enclosure containing either the circuit supply or the circuit load terminations, as covered in 110.14(C)(1)”. This requirement ensures that the reduced-ampacity conductor is used only where both ends land on the higher-rated pressure connectors and is not run into equipment where terminal temperature limitations would again dictate a higher conductor ampacity requirement.

The addition of this new exception creates consistent ampacity provisions across PV circuits, branch circuits, feeders, and interconnected power production sources. Installers now have a parallel allowance that better reflects how PV equipment is physically laid out, while inspectors gain clearer guidance for evaluating conductor transitions, connector temperature ratings, and the placement of intermediate junction points.

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 2026 NEC^® edition of NFPA 70.

2023 Code Language:

690.8(B)(1) Without Adjustment and Correction Factors. The minimum conductor size with an ampacity not less than the maximum currents calculated in 690.8(A) multiplied by 125 percent.

Exception: Circuits containing an assembly, together with its overcurrent device(s), that is listed for continuous operation at 100 percent of its rating shall be permitted to be used at 100 percent of its rating.

2026 Code Language:

690.8(B)(1) Without Adjustment and Correction Factors. The minimum conductor size with an ampacity not less than the maximum currents calculated in 690.8(A) multiplied by 125 percent.

Exception No. 1: Circuits containing an assembly, together with its OCPD, if any, that is listed for continuous operation at 100 percent of its rating shall be permitted to be used at 100 percent of its rating.

Exception No. 2: Where a portion of a circuit is connected at both its supply and load ends to separately installed pressure connections as covered in 110.14(C)(2), it shall be permitted to have an ampacity not less than the calculated maximum current of 690.8(A). No portion of the circuit installed under this exception shall extend into an enclosure containing either the circuit supply or the circuit load terminations, as covered in 110.14(C)(1).