Code Change Summary: Revisions clarify wiring terminology, relocate references for accuracy, and better align 690.31(C) with UL product designations for wire and cable.

SME commentary: The 2026 NEC^® updates to 690.31(C) focus on cleaning up terminology so the section lines up with how the related wire and cable products are actually listed. Earlier editions used the word “cable” in places where the product involved was clearly classified as a wire. UL 4703, for example, designates PV Wire as a wire product, and RHW-2 is also treated as a wire in the UL standards. By contrast, single conductor USE-2 and Type DG are cable products. The revised section title “Wires and Cables” reflects this mix more accurately, and the changes carry through in the text wherever specific wiring methods are mentioned.

Throughout the section, references to wiring methods were adjusted so they match the terminology found in the UL standards. Where the NEC^® intends to reference the Type PV Wire product, the section now uses that exact designation instead of the earlier phrase “PV wire or cable.” Situations involving both wires and cables, such as RHW-2, USE-2, and DG, are now described as “single conductor wires and cables” so the NEC^® mirrors the way these products are listed. When a requirement applies more broadly and is not tied to a specific wiring method, the NEC^® now uses the simpler term “conductors,” which prevents any unintended misapplication.

One of the more visible changes appears in the supporting and securing language. The former text in 690.31(C)(1)(b) has been expanded in the 2026 NEC^® to allow exposed conductors to be supported and secured by straps, hangers, or similar fittings, or other approved means designed and installed so as not to damage the conductors. The additional language raises awareness of the importance of choosing support or securement hardware that will not pinch, abrade, or otherwise compromise insulation in outdoor PV installations.

Listing requirements were removed and relocated to 690.2. Another key relocation involves the RHW-2 reference that previously sat under 690.31(C)(1)(b). Its previous position created the impression that the allowance to use PV wire anywhere RHW-2 is permitted applied only to conductors 8 AWG and smaller. Moving that sentence into the opening paragraph of 690.31(C) eliminates that misunderstanding and makes it clear that the permission applies to all conductor sizes covered in this section. The exception that used to appear at the end of 690.31(C)(1)(b) was also moved. It now sits at the end of the list under 690.31(C)(1)(d) so readers know that it applies to the entire set of installation requirements in 690.31(C)(1)(a through d), not only to exposed conductors addressed in 690.31(C)(1)(b).

A small editorial adjustment also appears in 690.31(C)(2)(c) where the word “or” was added between “ladder” and “trough” to better identify the two cable tray types referenced. These refinements make the section easier to read, bring it into better alignment with product listings, and support clearer and more consistent application for field installations.

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:

690.31(C) Cables. Type PV wire or cable and Type distributed generation (DG) cable shall be listed.

690.31(C)(1)(b) Exposed cables sized 8 AWG or smaller shall be supported and secured at intervals not to exceed 24 inches by cable ties, straps, hangers, or similar fittings listed and identified for securement and support in outdoor locations. PV wire or cable shall be permitted in all locations where RHW-2 is permitted.

2026 Code Language:

690.31(C) Wires and Cables. Type PV wire shall be permitted in all locations where Type RHW-2 is permitted. Type DG cable shall be permitted in all locations where Type TC is permitted.

690.31(C)(1)(b) Exposed conductors shall be supported and secured by one of the following methods:

(1) Cable ties that are listed and identified for securement and support in outdoor locations

(2) Straps, hangers, or similar fittings, or other approved means designed and installed so as not to damage the conductors

690.31(C)(1)(d) Conductors sized 8 AWG and smaller shall be supported and secured at intervals not to exceed 24 inches.