The National Electrical Code is updated every 3 years, but states adopt new editions on their own schedules — typically 2–5 years after publication. As of 2026, US states are spread across NEC 2017, 2020, and 2023.
This affects solar PV design because different NEC editions have different rapid shutdown requirements, grounding provisions, and energy storage rules. Designing to the wrong edition can result in permit rejection or failed inspection.
Local AHJ May Differ From State
Cities and counties can adopt NEC editions independently of the state. A city may be on NEC 2020 while the state is still on NEC 2017, or vice versa. The table below reflects state-level adoption. Always confirm the specific AHJ’s adopted edition by contacting the local building department or checking the city/county building code webpage.
NEC Adoption by State (2026)
| State | Adopted NEC Edition | Notes |
|---|---|---|
| Alabama | NEC 2020 | — |
| Alaska | NEC 2020 | — |
| Arizona | NEC 2020 | — |
| Arkansas | NEC 2020 | — |
| California | NEC 2020 | California Electrical Code amendments apply |
| Colorado | NEC 2023 | Early adopter; significant solar market |
| Connecticut | NEC 2020 | — |
| Delaware | NEC 2020 | — |
| Florida | NEC 2020 | Florida Building Code amendments apply |
| Georgia | NEC 2020 | — |
| Hawaii | NEC 2020 | Additional Hawaiian Electric requirements for solar |
| Idaho | NEC 2020 | — |
| Illinois | NEC 2020 | — |
| Indiana | NEC 2020 | — |
| Iowa | NEC 2020 | — |
| Kansas | NEC 2020 | — |
| Kentucky | NEC 2020 | — |
| Louisiana | NEC 2020 | — |
| Maine | NEC 2023 | — |
| Maryland | NEC 2023 | — |
| Massachusetts | NEC 2023 | Early adopter |
| Michigan | NEC 2020 | — |
| Minnesota | NEC 2020 | — |
| Mississippi | NEC 2020 | — |
| Missouri | NEC 2020 | — |
| Montana | NEC 2020 | — |
| Nebraska | NEC 2020 | — |
| Nevada | NEC 2020 | — |
| New Hampshire | NEC 2020 | — |
| New Jersey | NEC 2017 | Transition to NEC 2020 in progress (check AHJ) |
| New Mexico | NEC 2020 | — |
| New York | NEC 2020 | NYC has separate NYS Building Code |
| North Carolina | NEC 2020 | — |
| North Dakota | NEC 2020 | — |
| Ohio | NEC 2020 | — |
| Oklahoma | NEC 2020 | — |
| Oregon | NEC 2023 | Early adopter |
| Pennsylvania | NEC 2020 | — |
| Rhode Island | NEC 2023 | — |
| South Carolina | NEC 2020 | — |
| South Dakota | NEC 2020 | — |
| Tennessee | NEC 2020 | — |
| Texas | NEC 2020 | — |
| Utah | NEC 2020 | — |
| Vermont | NEC 2020 | — |
| Virginia | NEC 2023 | Virginia Uniform Statewide Building Code includes NEC 2023 |
| Washington | NEC 2023 | Early adopter; Seattle City Light has additional requirements |
| West Virginia | NEC 2020 | — |
| Wisconsin | NEC 2020 | — |
| Wyoming | NEC 2020 | — |
Key Differences Between NEC Editions for Solar PV
NEC 2017 vs. 2020
| Feature | NEC 2017 | NEC 2020 |
|---|---|---|
| Rapid shutdown (690.12) | 30V within array boundary within 30 sec | Clarified array boundary definition (1 ft perimeter) |
| Ground fault (690.41) | GFP required | Clarified for ungrounded/transformerless inverters |
| Energy storage | Article 706 added | Further updates to 706 |
| DC arc fault | Some provisions | Expanded requirements |
NEC 2020 vs. 2023
| Feature | NEC 2020 | NEC 2023 |
|---|---|---|
| Rapid shutdown | 30V/30-sec within array boundary | PVHCS (Photovoltaic Hazard Control System) alternative path added |
| Grounding electrode | DC GE for grounded systems >250V | Reorganized, clearer language |
| Energy storage | Article 706 | Updated 706 with battery system provisions |
| DC arc fault | AFCI requirements for some circuits | Expanded AFCI scope |
| Wiring methods | 690.31 | Minor clarifications |
NEC 2023 PVHCS: A New Compliance Path
NEC 2023 introduced the Photovoltaic Hazard Control System (PVHCS) as an alternative to the specific 30V/30-second rapid shutdown requirement. A PVHCS can use other means to address the firefighter safety concern — this opens the door for future rapid shutdown approaches beyond MLPE. For states on NEC 2023 (CO, OR, WA, VA, MA, MD, RI, ME), check with the AHJ whether they’ve provided guidance on PVHCS interpretation.
State-Specific Amendments That Affect Solar
California (NEC 2020 + California Electrical Code)
- Title 24 mandatory solar requirements for new construction
- CalFire wildfire setback requirements for rooftop solar
- Some CEC amendments create specific requirements not in base NEC
Florida (NEC 2020 + Florida Building Code)
- Hurricane wind load requirements (most stringent in continental US)
- Miami-Dade NOA product approval requirements
- FBC structural requirements for racking attachment
New York (NEC 2020 + NYC-specific)
- NYC Building Code has its own electrical provisions for NYC boroughs
- Upstate NY uses standard NEC 2020 with state adoptions
- NYC landmark building requirements for visible solar installations
Texas (NEC 2020)
- No statewide amendments for solar that significantly differ from base NEC
- Local AHJ variation is significant — 254 counties, each may interpret independently
Design to the Right NEC Edition Automatically
SurgePV selects the applicable NEC edition based on project location and ensures all calculations comply with the correct version — no manual code lookup required.
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Frequently Asked Questions
Which NEC edition do most states use in 2026?
NEC 2020 is the most widely adopted as of 2026. Early adopters on NEC 2023: Colorado, Oregon, Washington, Virginia, Massachusetts, Maryland, Rhode Island, and Maine. New Jersey remains on NEC 2017 (transitioning). Always verify with the local AHJ.
What changed in NEC 2023 for solar?
The biggest change is the introduction of PVHCS (Photovoltaic Hazard Control System) as an alternative compliance path for rapid shutdown. NEC 2023 also updated energy storage (Article 706), expanded DC arc fault provisions, and reorganized grounding electrode requirements.
Can a city use a different NEC edition than the state?
Yes. Local jurisdictions can adopt NEC editions independently of the state. Always confirm with the specific building department for the project address, especially in cities with active building code programs.
