Article 110.16 is Clarified in the 2026 NEC

Submitted by Mike Miller, Curriculum & Training Manager

The 2026 NEC is getting closer to being published with release of the Second Draft Report on March 5. I would like to review for you Article 110.16(B) that has raised some concern when it was changed in the 2023 NEC and how has been clarified though a major change coming out in the 2026 version. That change deals with the arc flash marking required on service equipment and feeder-supplied equipment.

The 2020 NEC, in Article 110.16(B), set the standard well by calling out the requirements for a permanent label for 1200 ampere or more services to include the following information:

1. Nominal system voltage
2. Available fault current at the service overcurrent protective devices
3. The clearing time of service overcurrent protective devices based on the available fault current at the service equipment
4. The date the label was applied

The 2023 NEC removed a good portion of part B of Article 110.16 found in the 2020 version and replaced it with “In other than dwelling units, in addition to the requirements in 110.16(A), a permanent arc flash label shall be field or factory applied to service equipment and feeder supplied equipment rated 1000 amperes or more. The arc flash label shall be in accordance with applicable industry practice and include the date the label was applied.”

It appears that the reference to applicable industry practice found in part B of the Article only offered the electrician the option of following information provided by Informational Note No. 2 when it came to generating a label for this equipment.

Informational Note No. 2 stated: See NFPA 70E-2021, Standard for Electrical Safety in the Workplace, for applicable industry practices for equipment labeling. This standard provides specific criteria for developing arc-flash labels for equipment that provides nominal system voltage, incident energy levels, arc-flash boundaries, minimum required levels of personal protective equipment and so forth.

Many AHJs, upon seeing this, opted not to enforce the label information in the Informational Note and suggested seeing how the 2026 NEC would deal with this significant issue.

Just to let you know, the text below represents the 70E statement on information for the equipment label.

The 2024 70E “Standard for Electrical Safety in the Workplace” In reviewing the NFPA 70E, Article 130.5(H) Equipment Labeling, it states:

“Electrical equipment such as switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers that are in other than dwelling units and that are likely to require examination, adjustment, servicing, or maintenance while energized shall be marked with a label containing all the following information:

1. Nominal system voltage
2. Arc flash boundary
3. At least one of the following:

a. Available incident energy and the corresponding working distance, or the arc flash PPE category in Table 130.7(C)(15)(a) or Table 130.7(C)(15)(b) for the equipment, but not both
b. Minimum arc rating of clothing
c. Site-specific level of PPE.”

The 2026 NEC provided an interpretation by stating the following relating to the required arc flash label: 110.16 Arc-Flash Hazard Marking.

In other than dwelling units, a permanent arc flash marking shall be field, or factory applied to service equipment and feeder-supplied equipment, such as switchboards, switchgear, enclosed panelboards, industrial control panels, meter socket enclosures, and motor control centers that are likely to require examination, adjustment, servicing, or maintenance while energized . The marking shall comply with 110.21(B), be located to be clearly visible to qualified persons, and be in accordance with applicable industry practice, containing the following information:

1. The nominal system voltage
2. The arc flash boundary
3. The available incident energy or minimum required level of personal protective equipment
4. The date the assessment was completed

We are hopeful a software application (app) will become available like the FC² that has no cost and is easy to use. Currently there are software packages available on the market that run from three to seven hundred dollars that do provide information for completing the label. As we become aware of such apps, we will share the information.

Please note that information contained herein relating to the 2026 NEC Article 110.16 is subject to change as the finished code has not been published as of date of this article.