The National Electrical Code (NEC) is published by NFPA on a three-year cycle. NEC 2023 (NFPA 70, 2023 edition) was published in August 2022 and has been progressively adopted by states through 2024–2026. For solar permit designers, each NEC cycle introduces changes to Article 690 (Solar Photovoltaic Systems), Article 706 (Energy Storage Systems), Article 230 (Services), and interconnected articles that affect what goes on every plan set, every SLD, and every permit package.
Getting caught drawing to NEC 2020 when an AHJ has adopted NEC 2023 produces two outcomes: plan corrections and permit delays. Getting the changes right from the start is the difference between a 4-business-day permit and a 14-business-day correction cycle. This post is a designer’s working reference — not a code commentary, but a change-by-change impact analysis organized by where each change appears in the permit package.
Direct answer. The most impactful NEC 2023 changes for solar permit designers are: (1) NEC 230.85 emergency disconnect — now required at the service entrance for new construction with certain occupancies; (2) Article 690 updates to rapid shutdown system zone definitions; (3) Article 706 updates to energy storage system disconnecting means and equipment listing requirements; and (4) revisions to 705.12 interconnection provisions. States adopting NEC 2023 as of mid-2026 include Colorado, Washington, Oregon, and others — verify your AHJ’s adopted code edition before submitting any plan set.
NEC Adoption Timeline — Which States Use Which Edition
The NEC is a model code. Each state (and sometimes each AHJ within a state) adopts it by reference at a specific edition. Misidentifying the adopted edition is one of the most common causes of plan corrections.
| State | Adopted Edition (as of June 2026) | Notes |
|---|---|---|
| Colorado | NEC 2023 | Adopted January 2024; statewide |
| Washington | NEC 2023 | Adopted 2024; statewide |
| Oregon | NEC 2023 | Adopted 2024 |
| California | NEC 2022 (California Electrical Code) | CA uses a modified NEC 2020 with state amendments, called CEC 2022 |
| Texas | No statewide; AHJ varies | Houston: NEC 2020; Dallas: NEC 2020; Austin: NEC 2023 adopted |
| Florida | NEC 2023 | Adopted statewide with state amendments |
| New York | NEC 2020 | NYC uses NEC 2020 + local amendments |
| New Jersey | NEC 2021 | State-adopted 2021 edition |
| Massachusetts | NEC 2020 | With Massachusetts amendments |
| Arizona | NEC 2017 or 2020 | Phoenix: NEC 2017; Scottsdale: NEC 2020; varies by AHJ |
| Illinois | NEC 2017 | Chicago: NEC 2017 + Chicago amendments |
| North Carolina | NEC 2020 | Statewide |
Watch out — verify before drawing. NEC adoption is not always immediate at the state level. Some AHJs within states that have "adopted" NEC 2023 still review against their previous edition during a transition period. Before starting any permit package, confirm the specific AHJ's adopted code edition — either from the AHJ's official website, the online permit portal, or a direct inquiry to the building department. Drawing to the wrong edition wastes 4–14 business days in a correction cycle.
Article 690 — Solar Photovoltaic Systems: Key NEC 2023 Changes
Article 690 is the primary solar code article. NEC 2023 introduces several significant changes from NEC 2020.
690.12 — Rapid Shutdown System (RSS)
NEC 2020 required rapid shutdown for all rooftop PV systems on buildings. NEC 2023 refines the requirements:
NEC 2020 — RSS Requirements:
- Conductors more than 1 foot inside a building or more than 3 feet from array edge: must be de-energized to ≤ 30V within 30 seconds of RSS initiation
- Module-level power electronics (MLPE) or array-level RSS devices required
- Limited Roof Access Zone: 3 feet from ridge, valley, hip, rake edge
NEC 2023 Changes to RSS:
- Clarification of the “controlled conductor” definition: clarifies which conductors require RSS compliance
- Revised definition of “PV Hazard Control System” — a broader term that encompasses RSS and additional safety measures
- New exception for specific array configurations that qualify for exemption
- Clarification that RSS applies to conductors in the building or within the “controlled zone” on the roof
SLD Impact:
- The RSS product must be explicitly identified on the SLD (not just “RSS system present”)
- The controlled zone boundary must be shown on the roof plan
- The initiation device location (utility disconnect, building exterior) must be labeled
690.31 — Wiring Methods
NEC 2020: Listed PV wire or USE-2 permitted in exterior array wiring.
NEC 2023 Changes:
- Additional clarity on conduit requirements for rooftop wiring that passes through the building penetration
- Clarification of underground wiring methods for ground-mount systems
- Updated requirements for wiring in direct burial applications
Drawing Impact: Conduit specifications on the SLD must reference the correct NEC 2023 wiring method designations. Systems designed to NEC 2020 wiring method conventions may use deprecated designations.
690.41 — System Grounding
NEC 2020: PV systems ≥ 50V must be grounded. Exceptions for ungrounded and impedance-grounded systems with specific safeguards.
NEC 2023 Changes:
- Updated alignment with NEC 250 equipment grounding requirements
- Clarification of grounding for systems with bifacial modules
- Updated requirements for grounding electrode conductors in large PV systems
690.56 — Identification and Disconnecting of PV Equipment
NEC 2020: Disconnecting means required; labeling requirements for DC disconnects.
NEC 2023 New Requirements:
- New label requirements specifying voltage and current ratings at the disconnect
- Clarification of disconnect location requirements relative to equipment rooms
- Updated labeling for systems with energy storage (combined PV + BESS systems)
SLD Impact: Disconnect labels on the SLD must match NEC 2023 label content requirements exactly. Many plan corrections result from labels that don’t include required voltage/current markings.
NEC 230.85 — Emergency Disconnect (New in NEC 2023)
NEC 230.85 is the most significant new provision in NEC 2023 for solar installations. It is the requirement that has triggered the most plan corrections and permit discussions in states that have adopted NEC 2023.
What NEC 230.85 Requires:
New construction with a service entrance must include an emergency disconnect — a single means to simultaneously de-energize all conductors entering the building from the utility service — accessible to emergency responders on the building exterior.
NEC 230.85 Text Summary:
- Applies to one-family and two-family dwellings, and multifamily buildings with individual dwelling unit services
- The emergency disconnect must be located on the exterior of the building
- Must be capable of de-energizing all service conductors simultaneously
- Must be labeled: “EMERGENCY DISCONNECT — SERVICE DISCONNECT” in a specific color/format
- Must be within 10 feet of the electric meter
Solar System Interaction:
For solar installations with load-side interconnection (the majority of residential systems), NEC 230.85 interacts with the system in a specific way:
- The emergency disconnect de-energizes the service conductors entering the building
- The solar system’s rapid shutdown system is triggered when the utility service is interrupted
- The combined effect is that emergency responders can de-energize both utility and solar feeds with defined, accessible disconnecting means
Plan Set Impact for NEC 2023 States:
- New construction solar: The SLD must show the NEC 230.85 emergency disconnect at the service entrance, exterior-mounted, within 10 feet of the meter
- Existing construction (retrofit solar): NEC 230.85 applies to new construction only; existing buildings adding solar are not retroactively required to install the emergency disconnect unless the service is being modified
- Label requirement: The SLD must include a callout for the NEC 230.85 emergency disconnect label: “EMERGENCY DISCONNECT — SERVICE DISCONNECT” — typically shown in red box on SLD
NEW CONSTRUCTION — NEC 2023
- NEC 230.85 emergency disconnect required
- Exterior-mounted, within 10 ft of meter
- Label: "EMERGENCY DISCONNECT — SERVICE DISCONNECT"
- Must appear on SLD and permit application
RETROFIT SOLAR — NEC 2023
- NEC 230.85 does NOT retroactively apply
- No emergency disconnect required for existing service
- RSS requirements still apply to the solar system
- Confirm with AHJ — some AHJs require 230.85 for any service upgrade
Article 706 — Energy Storage Systems: NEC 2023 Changes
Article 706 (Energy Storage Systems, ESS) was introduced in NEC 2017 and has been revised in each subsequent cycle. NEC 2023 brings important updates for BESS permit designers.
| Section | NEC 2020 Requirement | NEC 2023 Change | SLD Impact |
|---|---|---|---|
| 706.2 Definitions | ESS defined; terminology established | Revised definitions for “DC-coupled” and “AC-coupled” ESS configurations | Clarify system type on SLD |
| 706.4 Listing | Listed ESS equipment required | Strengthened: equipment must comply with UL 9540 or equivalent listing standard; UL 9540A thermal runaway testing reference added | Document UL 9540 listing number on cut sheet |
| 706.10 Disconnecting means | DC disconnect required | Updated location requirements; clarified requirements for accessible disconnects in residential applications | Show disconnect location on SLD; label per NEC 2023 |
| 706.15 Overcurrent protection | OCPD required for each ESS output circuit | Clarification of OCPD sizing for multi-source configurations (PV + ESS + utility) | Show OCPD rating on SLD |
| 706.22 Marking | Marking requirements for ESS enclosures | Expanded marking requirements including energy capacity in kWh | Add kWh marking to equipment schedule |
| 706.30 Storage battery installation | Installation requirements for battery banks | Updated clearance and ventilation requirements for lithium systems | Add ventilation note to plan if required |
NFPA 855 Interaction (Referenced in NEC 2023):
NEC 2023 explicitly references NFPA 855 (Standard for the Installation of Stationary Energy Storage Systems) for ESS installations. For residential lithium-ion BESS:
- Indoor standard installation: ≤ 20 kWh (per NFPA 855 Table 4.3)
- Indoor with listed containment system: higher quantities per product listing
- Outdoor: different thresholds apply
This NFPA 855 reference in NEC 2023 means that plan sets for systems near or above the 20 kWh threshold need documentation of the NFPA 855 compliance path. The NEC 706 BESS permit guide covers this in full detail.
Article 705 — Interconnected Electric Power Production Sources: NEC 2023 Changes
Article 705 governs how solar systems interconnect with utility power. NEC 2023 revisions affect the 120% busbar rule and multi-source configurations.
705.12(B) — Load-Side Connection (120% Rule)
NEC 2020: Solar OCPD ≤ (1.20 × busbar rating) − main breaker OCPD rating. End-fed rule applies for OCPD placement.
NEC 2023 Changes:
- Clarification of the end-fed rule: the solar OCPD must be at the opposite end of the busbar from the main breaker (not just anywhere on the busbar)
- Revised handling for multiple generation sources on the same busbar (PV + BESS + generator)
- Added clarification for AC-coupled battery systems: the battery inverter output OCPD counts in the 120% calculation the same as the solar inverter OCPD
SLD Impact:
- The 120% calculation box on the SLD must explicitly show all source OCPDs (solar + BESS + any generator)
- The calculation format must reflect NEC 2023 section references if the AHJ requires section citations
The NEC 705.12 deep dive covers the complete calculation methodology.
705.11 — Supply-Side Connection
NEC 2023 Changes:
- Clarification of supply-side tap conductor sizing requirements
- Updated guidance on supply-side connections for systems above 200A
Changes Affecting the SLD — Summary Checklist
For permit designers updating drawings from NEC 2020 to NEC 2023 standard:
Update NEC Edition Reference
Change "Designed to NEC 2020" → "Designed to NEC 2023 (NFPA 70, 2023 Edition)" in the title block or code compliance note. AHJs reviewing NEC 2023 plan sets will check this first.
Add NEC 230.85 Emergency Disconnect (New Construction Only)
For new construction projects in NEC 2023 states: show the exterior emergency disconnect on the SLD and site plan. Label it per NEC 230.85 requirements. Confirm with AHJ whether retrofit installations require it.
Update RSS Labeling (690.12)
Verify that the RSS product identification on the SLD uses NEC 2023 terminology ("PV Hazard Control System" in addition to RSS). Show the controlled zone boundary on the roof plan.
Update 120% Calculation Box (705.12)
For systems with both solar and BESS on load-side: ensure the 120% calculation includes both the PV inverter OCPD and the BESS inverter OCPD. Update section citation from "705.12(D)" (NEC 2020) to "705.12(B)" (NEC 2023) if the AHJ requires section references.
Update BESS Documentation (706)
For BESS-included systems: add UL 9540 listing confirmation, update disconnect location labels, add kWh capacity marking per 706.22. Reference NFPA 855 for indoor residential installations near the 20 kWh threshold.
Verify Wiring Method Designations (690.31)
Review all conduit and wiring method callouts on the SLD. Confirm that the method designations are current in NEC 2023. Some deprecated designations from NEC 2017/2020 may generate plan corrections.
NEC 2023 Changes Outside Article 690/706
Several articles outside the main solar articles have changes relevant to solar installations.
Article 230 — Services:
- NEC 230.85 (emergency disconnect) — the most impactful change, covered above
- NEC 230.82 — updated provisions for equipment connected ahead of service disconnect (supply-side solar tap applications)
Article 250 — Grounding and Bonding:
- Updated equipment grounding conductor sizing table
- Revised grounding requirements for separately derived systems that affect some solar + BESS configurations
Article 240 — Overcurrent Protection:
- Clarifications to OCPD sizing for multi-source DC circuits relevant to large string solar systems
Article 310 — Conductors:
- Updated conductor ampacity correction factors for high-temperature conduit fill scenarios common in rooftop solar wiring
Comparison Summary — NEC 2020 vs NEC 2023 Solar Impact
| Change | NEC 2020 | NEC 2023 | Impact on Plan Sets |
|---|---|---|---|
| Emergency disconnect | Not required for solar | 230.85 requires exterior emergency disconnect (new construction) | Add to SLD and site plan for new construction |
| RSS terminology | ”Rapid Shutdown System (RSS)" | "PV Hazard Control System” + RSS | Update SLD labels |
| RSS controlled zone | Defined by distance from edge | Clarified zone definition | Verify roof plan markup |
| 120% calculation | 705.12(D); PV OCPD counted | 705.12(B); PV + BESS OCPD both counted | Update calculation box for PV+BESS systems |
| BESS listing | Listed equipment required | UL 9540 explicitly referenced | Add UL 9540 notation to cut sheets |
| BESS disconnect | Required | Updated location requirements | Verify SLD disconnect location labels |
| BESS energy marking | Not explicitly required | kWh capacity marking required (706.22) | Add kWh to equipment schedule |
| NFPA 855 reference | Referenced by some AHJs | Explicitly referenced in NEC 2023 | Document NFPA 855 compliance for indoor BESS |
First-pass approval tip. The fastest way to avoid NEC edition-related plan corrections is to include a code compliance table on the SLD cover sheet listing: adopted NEC edition, key Article 690 provisions satisfied, RSS type and standard, 120% calculation result, and BESS compliance path (if applicable). AHJs reviewing NEC 2023 plan sets frequently flag any drawing that doesn't clearly identify which code edition was used — the table eliminates this ambiguity before the reviewer opens the drawing file.
How Heaven Designs Stays Current with NEC Editions
The NEC edition question is operationally managed at the AHJ research stage — before drawing begins. Heaven Designs maintains a current AHJ database that tracks adopted NEC edition, SolarApp+ status, and jurisdiction-specific amendments for every AHJ across all active project states.
38+
States covered with PE stamp and NEC-current plan sets
Heaven Designs, 2026
96.2%
First-pass AHJ approval rate across all USA plan sets
Heaven Designs internal, Q1 2026
4–7
Business days from site data to stamped permit packet delivery
Heaven Designs SLA
- Solar Permit Design (USA) — PE-stamped NEC 2023-compliant plan sets for all 38+ states. AHJ-verified code edition for every submission.
- Solar 3D Pre-Design — Sales-stage 3D + preliminary SLD before full permit package commitment.
- NEC 705.12 Interconnection Guide — Complete 120% busbar rule guide with calculation examples.
- NEC 706 BESS Permit Guide — Article 706 + NFPA 855 compliance for solar+storage permit packages.
The NFPA 70 (NEC) official page is the authoritative source for NEC 2023 text and adoption status. The NREL solar permitting research documents how NEC adoption timelines affect permit process efficiency across jurisdictions. The SEIA solar industry data tracks permit cost and timeline trends correlated with AHJ code edition. The ICC model codes platform provides supplementary information on how the NEC coordinates with the International Building Code and International Residential Code for solar permit purposes.
Glossary: NEC 705, AHJ, Rapid Shutdown.
FAQ
What is the most important NEC 2023 change for residential solar permit designers?
NEC 230.85 (emergency disconnect at service entrance) is the most impactful new provision for residential solar in NEC 2023. It requires new construction with a service entrance to include an exterior emergency disconnect that can de-energize all service conductors, with specific labeling and location requirements within 10 feet of the meter. For solar installations on new construction in states that have adopted NEC 2023 (Colorado, Washington, Florida, Oregon, others), this provision must be shown on the SLD and site plan — and missing it is a common first-cycle plan correction.
Does NEC 230.85 apply to existing homes getting solar?
NEC 230.85 (emergency disconnect) is a new construction requirement — it applies when a new service entrance is installed. For existing homes receiving a solar installation without a service entrance upgrade, NEC 230.85 does not retroactively apply. However, if the solar installation also includes a service panel upgrade (increasing from 100A to 200A, for example), some AHJs in NEC 2023 states interpret this as a service modification that triggers NEC 230.85. Confirm with the specific AHJ before designing the system — this interpretation varies.
What changed in NEC 2023 for solar+battery storage systems?
NEC 2023 updates to Article 706 include: explicit reference to UL 9540 listing for ESS equipment; updated disconnecting means requirements with specific location guidance; expanded marking requirements under 706.22 that require kWh energy capacity labeling; and explicit reference to NFPA 855 for indoor residential lithium-ion installations. The most commonly triggered correction: failing to document UL 9540 listing for the specific battery product on the cut sheet, or not referencing NFPA 855 for indoor BESS near the 20 kWh residential threshold.
Is NEC 2023 adopted in California?
California uses its own California Electrical Code (CEC), which is based on NEC 2020 with California-specific amendments and is updated on a separate schedule from the national NEC cycle. The CEC 2022 (effective 2023) is the current California electrical code — it incorporates NEC 2020 with state amendments but is not the same as NEC 2023. Solar designers working in California should design to CEC 2022 provisions, not NEC 2023. LADBS, DSD, RCPD, and other California AHJs enforce the CEC, not the national NEC 2023.
How do I find out which NEC edition my AHJ uses?
The fastest method: check the AHJ’s official building department website for a “code adoptions” or “applicable codes” page. Many AHJs list their current code editions on their permit application forms. For AHJs that don’t publish this information, a direct call to the plan check counter (“what edition of the NEC do you currently enforce?”) gets a definitive answer in 2–3 minutes. SolarApp+ submissions automatically verify code edition at the AHJ level for qualifying systems — but for manual plan check submissions, pre-verifying the code edition is a first-pass approval prerequisite.
What is the difference between NEC 2020 section 705.12(D) and NEC 2023 section 705.12(B)?
In NEC 2020, the load-side interconnection 120% rule was located at section 705.12(D). In NEC 2023, the same provision was reorganized to section 705.12(B). The mathematical content of the rule (Solar OCPD ≤ 1.20 × busbar rating − main breaker OCPD) is essentially the same, but the section number changed. AHJs enforcing NEC 2023 will expect section citations on plan sets to reference 705.12(B), not 705.12(D). Using the NEC 2020 section number on an NEC 2023 plan set can trigger a minor correction — update section references when transitioning templates to NEC 2023.
