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NEC 2026 §110.16 — Arc-Flash Hazard Marking

New arc flash labeling requirements

The 2026 NEC requires equipment-specific arc flash markings on service and feeder-supplied equipment outside dwelling units when the equipment is likely to require examination, adjustment, servicing or maintenance while energized. Section 110.16 has no amperage threshold.

What changed

  • Section 110.16 renamed: "Arc-Flash Hazard Warning" → "Arc-Flash Hazard Marking."
  • The rule covers service and feeder-supplied equipment likely to require energized examination, adjustment, servicing or maintenance. Examples include switchboards, switchgear, enclosed panelboards, industrial control panels, meter socket enclosures and motor control centers. Dwelling units are excluded.
  • Every label must state: nominal system voltage, arc flash boundary, available incident energy or minimum PPE level, and the date the assessment was completed.
  • The date is the assessment completion date. The marking must be permanent, visible to qualified persons before the work, and meet 110.21(B).

How this may affect your facility

  • For installations subject to the adopted 2026 NEC requirements, a generic warning alone does not supply the equipment-specific information in 110.16. Confirm local adoption, amendments and applicability with the authority having jurisdiction.
  • NFPA 70E-2027 requires accuracy reviews at intervals no longer than five years. Check the assessment and documented review records. Update the assessment when system changes could affect results, and update labels when the reviewed data renders them inaccurate.

Questions about a specific facility can go to studies@heirarc.com.

Sources

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