This article is part of the Print Pro AZ arc flash labeling series. Start with the pillar guide: Arc Flash Labels: NFPA 70E 2024 Requirements Guide.
NEC 2026 Section 110.16 removed the 1,000-ampere threshold that previously limited arc flash labeling to large equipment. All service and feeder-supplied equipment in non-residential buildings now requires an arc flash hazard label, regardless of amperage. Labels must include the nominal system voltage, arc flash boundary, available incident energy or minimum PPE level, and the date the arc flash assessment was completed.
You have a 400-amp commercial panel in a tenant suite. Under NEC 2023, no arc flash label required -- the old threshold was 1,000 amps. Under NEC 2026, that panel needs a label. Same building, same panel, different code cycle.
This is the biggest single change to arc flash labeling in the NEC's history. It closes a gap that existed for years: small and medium commercial panels were exempt from formal arc flash marking even though they posed real hazards to the electricians working on them. NEC 2026 Section 110.16 ends that exemption.
If you work in California or another jurisdiction that has adopted NEC 2026, this affects your current projects now. If your state is still on 2023 or 2020, this is the rule you are working toward. This guide explains exactly what changed, what labels must include, and how Print Pro AZ helps commercial contractors meet the new standard.
What Exactly Changed in NEC 2026 Section 110.16?
The section was renamed. Previous editions called it "Arc-Flash Hazard Warning." NEC 2026 renamed it "Arc-Flash Hazard Marking." The word change matters: "warning" is a general communication concept; "marking" is a specific physical action that must be completed on specific equipment.
The core change: the 1,000-amp threshold is gone.
- NEC 2023 Section 110.16(B): Arc flash marking required on service equipment and feeder-supplied equipment rated 1,000 amperes or more in other than dwelling units.
- NEC 2026 Section 110.16: Arc flash marking required on all service and feeder-supplied equipment in other than dwelling units -- no amperage threshold.
Equipment covered under NEC 2026:
- Switchboards and switchgear
- Enclosed panelboards
- Industrial control panels
- Meter socket enclosures
- Motor control centers
One- and two-family dwellings remain exempt. Multi-family residential buildings, commercial offices, retail spaces, industrial facilities, schools, hospitals, and every other non-dwelling occupancy are covered.
What the label must include (four required elements):
- Nominal system voltage -- the operating voltage at the equipment
- Arc flash boundary -- the distance at which incident energy equals 1.2 cal/cm2
- Available incident energy at the specified working distance, OR the minimum level of PPE required
- The date the arc flash assessment was completed -- this is new and important
The date requirement was not present in prior NEC editions in this form. NEC 2026 requires the assessment date, not the date the label was applied. If a study was done in 2022 and someone finally applied the label in 2026, the label must show 2022 -- when the study was actually performed.
Why Was the Threshold Removed?
The 1,000-amp threshold made sense when it was introduced -- larger equipment generally has higher incident energy and poses greater risk. But it created a gap: small commercial panels below 1,000 amps were exempt from formal arc flash marking even though electricians work on them energized all the time.
A 400-amp, 480V commercial panel can generate significant arc flash incident energy. The hazard does not disappear because the panel is small. NFPA 70E 2024 Section 130.5(H) requires arc flash assessment and labeling on any equipment that may be worked on while energized -- regardless of amperage. NEC 2026 brought the NEC into alignment with NFPA 70E on this point.
The alignment also closes an OSHA gap. OSHA has no specific arc flash labeling regulation, but enforces through the General Duty Clause with NFPA 70E as the recognized industry standard. A facility that complied with NEC but skipped small panel labels could still face OSHA exposure under NFPA 70E. NEC 2026 makes the NEC and NFPA 70E consistent.
Inspection Tip: California adopted NEC 2026 effective January 1, 2026. If you are pulling permits in California on commercial work, every panel -- regardless of size -- needs an arc flash label. An inspector who knows the 2026 code will check for this. A 200-amp tenant suite panel with no arc flash label is a violation under NEC 2026 Section 110.16.
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What Must Be on the Label?
Per NEC 2026 Section 110.16, every arc flash label must show all four required elements:
1. Nominal System Voltage The operating voltage at the equipment. For a standard commercial panel fed from a 120/208V three-phase system, the label shows 208V (or the specific voltage as appropriate). This tells the worker and the responder what voltage they are dealing with before they open the door.
2. Arc Flash Boundary The calculated distance from the equipment at which incident energy equals 1.2 cal/cm2. A person outside this boundary with no arc flash PPE would receive at most a second-degree burn in a worst-case arc event. Inside this boundary, arc-rated PPE is required. The boundary is equipment-specific -- it comes from an arc flash study.
3. Available Incident Energy OR Minimum PPE Level The label must show one of:
- The available incident energy (in cal/cm2) at the specified working distance -- the incident energy method
- The minimum level of PPE required -- the PPE category method (Category 1 through 4 per NFPA 70E)
Both methods are valid. The label cannot show both on the same placard. Pick one method and apply it consistently across the facility.
4. Date of Arc Flash Assessment The date the engineering study that produced the label data was completed. Not the installation date of the label. Not the last inspection date. The assessment date. If the study needs to be updated, the outdated label date is the trigger for workers and facility managers to request a new study.
| Required Element | Example |
|---|---|
| Nominal voltage | 480V |
| Arc flash boundary | 24 inches |
| Incident energy (or PPE) | 4.3 cal/cm2 at 18 inches (or: PPE Category 2) |
| Assessment date | March 15, 2025 |
How Do I Get the Data for the Labels?
NEC 2026 Section 110.16 requires that equipment be marked "based on an arc flash risk assessment in accordance with 130.5 of NFPA 70E." This means the data must come from a formal arc flash study performed by a qualified engineer using IEEE 1584-2018 methodology.
The process:
- Commission a licensed electrical engineer to perform an arc flash study for your facility
- The engineer calculates incident energy and arc flash boundaries for each piece of equipment covered under 110.16
- Labels are produced based on the study data
- Labels are applied to equipment before the project receives final inspection
- The label program is maintained -- updated when system changes occur, at minimum every 5 years per NFPA 70E
For commercial tenant finish work and smaller commercial projects, the arc flash study may be the responsibility of the building owner rather than the tenant improvement contractor. Verify who owns the label obligation on your contract before final inspection.
Who Is Affected by NEC 2026 Section 110.16?
The short answer: any commercial building in a NEC 2026 jurisdiction.
Currently in NEC 2026 jurisdiction:
- California (effective January 1, 2026)
Working toward NEC 2026 adoption: Most states adopt a new NEC edition within 2-4 years of its release (2025). If your state is on NEC 2023 or 2020 today, expect NEC 2026 adoption in the next 1-3 years. AHJs vary -- always verify which edition your specific jurisdiction has adopted before pulling permits.
For the purposes of this change:
- Existing buildings in NEC 2026 jurisdictions: Existing panels are generally not retroactively required to add arc flash labels unless the equipment is modified or the permit process is triggered. New installations and major modifications are subject to 2026 requirements.
- New construction in NEC 2026 jurisdictions: All covered equipment must have arc flash labels before final inspection.
- States on earlier NEC editions: The 1,000-amp threshold still applies. Plan your label program around your jurisdiction's adopted code.
Print Pro AZ supplies arc flash hazard labels and complete electrician label packs to commercial contractors across the country. Our electrician labels collection includes high-voltage warning, arc flash symbol, and hazardous voltage labels in six sizes, on UV-resistant vinyl. For large commercial projects requiring custom arc flash labels with specific voltage, boundary, and PPE data, send us your plan sets.
How Does NEC 2026 Align with NFPA 70E 2024?
NEC 2026 Section 110.16 explicitly states that labels must be based on "an arc flash risk assessment in accordance with 130.5 of NFPA 70E." Prior NEC editions referenced "applicable industry practice" -- a vague standard that let facilities claim various approaches. NEC 2026 names NFPA 70E directly.
The key alignment points between NEC 2026 110.16 and NFPA 70E 2024 130.5(H):
- Both require the assessment date on the label (NFPA 70E added this in prior editions; NEC 2026 now matches)
- Both require either incident energy or PPE category, but not both
- NEC 2026 expands the scope of covered equipment to match NFPA 70E's broader "equipment likely to require energized work" criteria
The practical result: a facility that fully complies with NFPA 70E 130.5(H) will generally comply with NEC 2026 110.16, and vice versa. The days of citing one standard to avoid the other are over.
FAQ: NEC 2026 Section 110.16 Arc Flash Labels
Does NEC 2026 require arc flash labels on residential panels? No. Section 110.16 applies to "other than dwelling units." One- and two-family residential panels are exempt. Multi-family residential buildings (apartments, condos) are generally not considered dwelling units under the NEC and are subject to the commercial requirements.
What is the assessment date requirement and why does it matter? NEC 2026 requires that the label show the date the arc flash assessment was completed -- not the date the label was installed. This matters because arc flash studies must be updated after system changes and every 5 years per NFPA 70E. A label showing an old assessment date tells workers the data may be outdated and prompts facility managers to commission an updated study.
What was the previous amperage threshold and why did it change? NEC 2023 required arc flash labels only on equipment rated 1,000 amperes or more. This was reduced from 1,200 amps in earlier editions. NEC 2026 removed the threshold entirely, because smaller commercial panels can still present significant arc flash hazards. The change aligns the NEC with NFPA 70E, which does not use an amperage threshold.
Can I use PPE category instead of incident energy on the label? Yes. NEC 2026 allows either approach. The PPE category method uses NFPA 70E tables to assign a category (1-4). The incident energy method uses IEEE 1584 calculations to determine specific cal/cm2 values. Both are valid. You cannot use both on the same label -- choose one method and apply it consistently.
Which states have adopted NEC 2026? California adopted NEC 2026 effective January 1, 2026, making it the first state to enforce this edition. Most other states are still on NEC 2023 or NEC 2020. AHJs vary even within states -- always verify with your local authority having jurisdiction which NEC edition governs your specific project.
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Three Takeaways and Next Steps
- NEC 2026 Section 110.16 removed the 1,000-amp threshold. Every non-residential, non-dwelling panel fed from the service or a feeder now needs an arc flash label -- regardless of size. This is a major scope expansion.
- The label must include four elements: nominal voltage, arc flash boundary, incident energy OR minimum PPE, and the date the assessment was completed. The date requirement is new and inspector-visible.
- California is the first state enforcing NEC 2026. If you work in California, this applies to your permits right now. Other states will follow within the next few years.
Have a commercial job? Send us your plan sets and Print Pro AZ will build your arc flash and electrical label package. Contact us here or call Brent: (602) 649-5305
Brent Hanke | Print Pro AZ | (602) 649-5305 | b.hanke@printproaz.com Brent Hanke is the founder of Print Pro AZ, supplying NEC-compliant labels to contractors across the country. Last Updated: 2026-09-24
Related reading: OSHA Arc Flash Requirements: 2024 OSHA 4472 Guide