NEC 2026 Preview: Key Code Changes Solar Installers Need to Prepare For

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The 2026 edition of the National Electrical Code (NEC) represents one of the most significant revisions in recent memory. With a sweeping reorganization underway, new articles for high-voltage systems, and targeted changes to PV rapid shutdown requirements, solar installers and electrical contractors need to understand what is changing and when their jurisdiction may adopt the new code. This preview covers the key developments as of mid-2025.

The Big Picture: NEC Reorganization

According to NFPA's NEC 70 code development page, the NEC Correlating Committee and Code-Making Panels 1–18 are executing a comprehensive reorganization that began with the 2023 edition. The 2026 edition continues this restructuring, with the goal of completing the reorganization in the 2029 edition.

For solar contractors, the most visible structural changes include:

• Article 220 relocation: Branch-Circuit, Feeder, and Service Load Calculations has been reorganized and moved to Chapter 1 as new Article 120.
• High-voltage articles: Five new articles were added to Chapter 2 to consolidate all requirements for installations over 1000 volts AC and 1500 volts DC — directly relevant to large-scale PV systems:
  • Article 265: Branch Circuits Over 1000V AC / 1500V DC
  • Article 266: Feeders Over 1000V AC / 1500V DC
  • Article 267: Outside Branch Circuits and Feeders Over 1000V AC / 1500V DC
  • Article 268: Services Over 1000V AC / 1500V DC
  • Article 270: Grounding and Bonding of Systems Over 1000V AC / 1500V DC
• Chapter 7 restructure: New articles 720–723, 742, and 750 consolidate limited-energy system requirements, with all grounding requirements for limited-energy systems now located in one place.

This reorganization means that contractors working on utility-scale solar projects — which increasingly operate at DC voltages exceeding 1500V — will find requirements consolidated in dedicated articles rather than scattered across the code.

Rapid Shutdown: TIA 1835 and Section 690.12(C)

The most directly PV-relevant change in the 2026 NEC comes through Tentative Interim Amendment (TIA) 1835, which revises Section 690.12(C) on rapid shutdown initiation devices. According to EC&M's coverage of the proposed TIAs, the key requirements are:

• Initiation devices must be readily accessible and consist of one or more of the following, as specified in the rapid shutdown equipment instructions:
  • Service disconnecting means
  • PV system disconnecting means
  • Listed switches
• For one- and two-family dwellings, initiation devices, where required, shall be located at an outdoor location.

This change strengthens firefighter safety by ensuring that rapid shutdown can be initiated from an accessible, outdoor location on residential properties. Installers should verify that their rapid shutdown system designs place initiation devices in compliant locations.

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GFCI and SPGFCI Changes

Outdoor Outlet GFCI Requirements — Section 210.8(F)

The 2026 NEC expands GFCI protection for outdoor outlets. Outlets rated 60 amperes or less are now required to have ground-fault circuit-interrupter (GFCI) protection. A new Exception No. 3 permits the use of a listed Class C special purpose ground-fault circuit-interrupter (SPGFCI) to protect listed HVAC equipment. These devices are listed to UL 943C.

This is particularly relevant because Exception No. 2 — which previously provided an alternative for HVAC equipment — expires on September 1, 2026. Contractors installing or servicing HVAC equipment alongside solar installations should plan for the transition to SPGFCI protection.

TIA 1843: GFCI Between Power Conversion Equipment and Motors

TIA 1843 adds a new Section 430.132, which states that ground-fault circuit interrupters and special purpose ground-fault circuit interrupters shall not be installed between power conversion equipment output terminals and the motor. This TIA applies to both the 2023 and 2026 editions, addressing a configuration that could cause nuisance tripping or equipment malfunction in systems using power conversion equipment.

DC Disconnect and Labeling Requirements

While Article 690's core DC disconnect requirements remain structurally similar to the 2023 edition, the reorganization and public comment process introduced clarifications. Per the NEC public comment record, key provisions include:

• Marking DC PV circuits: Permanent, readily visible labels indicating the highest maximum DC voltage in PV systems shall be provided at the DC PV system disconnecting means or PV system electronic power conversion equipment.
• PV system disconnect identification: The PV system disconnect must indicate whether it is in the open (OFF) or closed (ON) position and must be marked "PV SYSTEM DISCONNECT" or equivalent.
• Lockable enclosures: The door or hinged cover for the PV system disconnect must be locked or require a tool to open.
• Overcurrent device marking: Overcurrent protective devices used in PV system DC circuits shall be marked "Photovoltaic" or "PV."

These labeling requirements ensure that first responders and maintenance personnel can quickly identify and isolate PV system components. Contractors should stock compliant labeling materials and verify that all installed disconnects carry the required markings.

Find compliant DC disconnects and labeling accessories in our catalog.

PV Wire Sizing and Circuit Requirements

The fundamental PV circuit sizing methodology in Article 690 remains consistent with prior editions, but contractors should be aware of the following provisions as they prepare for 2026 NEC adoption:

• Maximum PV system DC circuit voltage (Section 690.7) is the highest voltage between any two conductors of a circuit, used for selecting conductors, cables, and equipment.
• Current calculation: For PV systems rated below 100 kW, the maximum PV system circuit current is 125% of the sum of the short-circuit current ratings of PV modules connected in parallel (Section 690.8(A)(1)(a)(1)).
• Conductor ampacity: PV circuit conductors must have an ampacity of at least 125% of the current as determined by Section 690.8(A), with an exception for assemblies listed for operation at 100% of their rating.

These requirements underscore the importance of proper wire sizing in PV source and output circuits. Undersized conductors remain one of the most common inspection findings on solar installations.

Load Calculation Changes That Affect Solar

While not PV-specific, changes to dwelling unit load calculations in the reorganized Article 120 (formerly Article 220) will affect how contractors size services and feeders for residential solar installations:

• The total volt-amperes per square foot for general lighting and receptacles in dwelling units was reduced from 3 VA/ft² to 2 VA/ft², reflecting increased energy efficiency in lighting and equipment.
• However, new Section 120.13 requires branch circuit load to be calculated at 3 VA/ft² to avoid a reduction in the number of branch circuits — meaning the change primarily affects service sizing, not circuit count.
• New Section 120.5(E) removes the requirement that continuous loads be calculated at 125%, a change that may simplify load calculations for solar-backed-up circuits.

These changes may reduce calculated service sizes for new residential construction, which could affect the available capacity for adding solar plus storage systems.

Adoption Timeline and Preparation

The NEC is typically adopted on a state-by-state basis, with adoption cycles ranging from immediate to several years after publication. As of mid-2025, the NFPA Standards Council was processing the six proposed TIAs, with a comment closing date of July 22, 2025. The table below summarizes the key TIAs affecting solar and electrical contractors:

TIA 1835 is the only PV-specific proposal in this batch, but all six, if issued by the NFPA Standards Council, will appear in the first printing and online version of the 2026 edition.

Contractors should take the following steps to prepare:

• Review the 2026 NEC when it becomes available, focusing on Article 690 changes and the new high-voltage articles (265–270) for utility-scale projects.
• Update rapid shutdown designs to ensure initiation devices are readily accessible and, for residential projects, located outdoors.
• Plan for GFCI/SPGFCI transition on HVAC equipment before the September 1, 2026 deadline for Exception No. 2 expiration.
• Verify labeling compliance on all PV disconnects and DC circuit markings.
• Coordinate with your AHJ to understand local adoption timelines and any amendments.

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Sources

• NFPA — NEC 70 Code Development
• NFPA — What Changed in the 2026 NEC?
• EC&M — Six New TIAs Proposed for 2026 NEC
• EC&M — NEC Requirements for Solar, Part 2
• EC&M — NEC Requirements for Solar, Part 3
• NFPA — NEC Public Comment Submittals, Panel 4