Arc Flash Label Requirements: NEC 2026 §110.16 and NFPA 70E §130.5(H)

Three rule sets decide what goes on an arc flash label in the US: the National Electrical Code (NEC), NFPA 70E, and OSHA. They overlap, but they are not interchangeable, and NEC 2026 changed the scope of the NEC side in a way that kills the generic warning sticker.

The short version, citable:

• NEC 2026 §110.16 requires a detailed arc-flash label on essentially all non-dwelling service and feeder equipment — the old 1,000 A threshold is gone — and the label must now show the date the assessment was completed.
• NFPA 70E §130.5(H) sets the label's content: nominal system voltage, the arc-flash boundary, and the incident energy or PPE level.
• OSHA 29 CFR 1910.333 is the enforcement hook. It requires safe work practices around energized equipment and points to NFPA 70E as the consensus standard for how that is done.

Last reviewed: July 18, 2026. Standards references verified against the sources listed at the bottom of this page.

What changed in NEC 2026 §110.16

Per EC&M's coverage of the 2026 code cycle (February 13, 2026), three changes matter for labels:

1. The 1,000 A threshold is removed. Earlier code editions limited the detailed arc-flash label requirement to equipment rated 1,000 A or more. NEC 2026 §110.16 applies the detailed-label rule to non-dwelling service and feeder equipment generally.
2. The label must show the date the assessment was completed. This replaces the older practice of dating the label when it was printed or applied. The date on the label now answers "how old is the analysis," not "how old is the sticker."
3. Generic warning stickers are effectively dead. A label that only says "Warning: Arc Flash Hazard" without equipment-specific values does not carry the information the section requires.

Adoption pacing is worth knowing: at research time (July 2026), no state had adopted NEC 2026, Washington is targeting December 31, 2026, and Maine is moving to amend §110.16 back out. That pacing does not create a grace period in practice, because the baseline forcing already exists today: NFPA 70E §130.5(H) detailed labels plus OSHA 1910.333 apply regardless of which NEC edition your state runs on.

What NFPA 70E §130.5(H) requires on the label

NFPA 70E is the workplace-electrical-safety standard. Where the NEC governs installation, 70E governs the work. Section 130.5(H) requires equipment to be field-marked with a label containing:

• Nominal system voltage
• Arc-flash boundary
• The method-specific PPE basis: incident energy at the working distance for an incident-energy analysis, or the PPE category when the category method applies

Do not convert incident energy into a PPE category. Calculated labels should state the incident energy and minimum arc-rating basis; category-method labels should state the category and table basis.

Two 70E-2024 details worth knowing:

• Exception 2 to §130.5(H) explicitly permits QR-code-accessible label formats in supervised industrial installations. A QR code may supplement the printed data. It never replaces it — the required values stay on the label itself.
• The review interval is five years, maximum. The risk assessment behind the label must be reviewed at intervals not exceeding five years, and sooner when the system changes.

Where OSHA fits

OSHA does not publish a label format. 29 CFR 1910.333 ("Selection and use of work practices") requires employers to use safety-related work practices around energized equipment, and OSHA's enforcement practice treats NFPA 70E as the national consensus standard for what those practices look like. OSHA updated its arc-flash guidance in November 2024, which raised enforcement attention on exactly this paperwork.

The practical read: if OSHA walks in after an incident, the question is not "which NEC edition is adopted here." It is "show me the assessment and the label for this equipment."

NEC 2026 §110.16 vs NFPA 70E §130.5(H), field by field

Requirement	NEC 2026 §110.16	NFPA 70E §130.5(H)
What it governs	Equipment installation and marking	Workplace safety; field-applied label after risk assessment
Scope	Non-dwelling service and feeder equipment (1,000 A threshold removed)	Equipment likely to require examination, adjustment, servicing, or maintenance while energized
Nominal system voltage	Required	Required
Arc-flash boundary	Required	Required
Incident energy or PPE level	Required (either; both permitted)	Required (at least one; both permitted)
Assessment completion date	Required — new in 2026	Tracked through the 5-year review cycle
Generic warning-only sticker	Does not comply	Does not comply
QR-accessible format	Addressed in code commentary	Permitted by Exception 2 in supervised industrial installations

What a complete label shows, as a checklist

Pulling the NEC and 70E requirements together with what public project specifications repeatedly demand, a label that survives inspection shows:

1. Nominal system voltage (e.g., 480Y/277 V, 3-phase).
2. Arc-flash boundary in inches or feet.
3. Incident energy in cal/cm² at the stated working distance, PPE level, or both.
4. The date the assessment was completed — the NEC 2026 change. Not the print date.
5. A study or label ID with an issue date. Spec'd jobs ask for "study report number and issue date" traceability; a label ID that maps back to a stored calculation record covers this.
6. Available fault current and the date it was obtained, matching NEC 110.24 service-marking practice. Not strictly a 110.16 field, but inspectors expect it and it documents the input the calculation depends on.
7. A documented signal-word policy. WARNING versus DANGER is a hazard-communication decision for the equipment owner; IEEE 1584 does not create an automatic 40 cal/cm² threshold. This tool uses WARNING by default.

Label sizes, materials, and print method

Requirements decide the content; specifications decide the physical label. Across six or more public project specifications (Delaware DNREC, City of Tampa, and housing-authority switchboard specs among them), the pattern is consistent:

• Sizes: 4×6 in and 4×4 in dominate. 3.5×5 in (89×127 mm) appears in federal specifications and is the common bilingual stock size. 6×8 in shows up for large switchgear lineups.
• Layout: ANSI Z535.4 — signal-word header, hazard symbol, and the message panel with the data fields.
• Stock: UL 969 adhesive polyester or vinyl, UV-resistant.
• Print method: thermal transfer, machine printed. The recurring spec language is "no field markings" — hand-written values fail spec'd jobs.
• Direct-thermal caution: desktop direct-thermal printers produce labels that fade and are not UV-stable. Acceptable indoors at your own risk; not what the specs describe.

When is an arc flash label required?

The trigger language across NEC 110.16 and NFPA 70E is the same idea: equipment likely to require examination, adjustment, servicing, or maintenance while energized. In practice that means panelboards, switchgear, MCCs, industrial control panels, disconnects, and transformers in non-dwelling buildings — if a qualified person will ever open it hot, it needs the label.

Dwelling units are outside the NEC 2026 expansion. Temporary de-energized-only equipment is the narrow exception, and "we always de-energize" is a claim the assessment record should back up, because verification of de-energization is itself energized work under 70E.

Get the numbers for your labels

The label is only as good as the incident-energy value behind it. Our free arc flash calculator runs the IEEE 1584-2018 method from your panel specs — voltage, available fault current, clearing time, electrode configuration — shows every intermediate value, and formats the result onto a label that follows NFPA 70E §130.5(H). The arc flash label template page covers the physical layout and sizes; the arc flash study cost page explains when you need a full engineering study and when a per-panel calculation covers you. If you are missing the fault-current input, start with what is available fault current.