NEC 2023: Section 110.16(B) Arc-Flash Labeling Update (What Changed & What To Do)
The 2023 National Electrical Code (NEC) continues to tighten expectations around electrical safety—especially
when it comes to arc-flash hazard labeling. If you manage commercial or industrial electrical equipment, the update to
NEC 110.16(B) is one you’ll want to understand and apply correctly.
Quick background: what NEC 110.16 is trying to accomplish
Arc flash events can be catastrophic. NEC 110.16 is designed to make sure that anyone working on energized equipment gets a
clear, visible warning that an arc-flash hazard may exist—and that additional protective steps may be required
before inspection, adjustment, servicing, or maintenance.
What 110.16(A) already requires
Under NEC 110.16(A), many common pieces of electrical equipment in other than dwelling units must
have a warning label when that equipment is likely to be worked on while energized. This commonly includes items like:
- Switchboards and switchgear
- Enclosed panelboards
- Industrial control panels
- Meter socket enclosures
- Motor control centers
In plain English: if it’s the type of equipment that may need hands-on work while energized, NEC expects a clear arc-flash hazard warning.
The NEC 2023 update: what 110.16(B) adds
NEC 110.16(B) goes a step further for larger systems. In the 2023 NEC, the requirement emphasizes an additional
arc-flash label for certain high-capacity equipment in other than dwelling units, including:
- Service equipment rated 1000 amps or more
- Feeder-supplied equipment rated 1000 amps or more
This label is in addition to the general warning label required by 110.16(A). It’s essentially a higher level of
labeling attention for higher-current equipment where the hazard potential can be greater.
What should the 110.16(B) label include?
The NEC points to “applicable industry practice” for how the label is produced and what it communicates. At a minimum, the label should:
- Be created according to recognized industry practices for arc-flash labeling
- Include the date the label was applied
- Be clearly visible and durable for the environment where it’s installed
Many facilities align their labels with standards used in the field (commonly referenced in NEC informational notes), so that labels are
consistent, readable, and meaningful to qualified workers.
Why this matters for businesses and facilities
If your facility has 1000A+ service equipment or large feeder-supplied gear, this update can affect
compliance planning, project closeouts, and safety programs. Proper labeling helps:
- Support a safer work environment for qualified personnel
- Reduce inspection issues and last-minute corrections
- Create clearer expectations for maintenance and service work
- Keep documentation and field conditions aligned
Practical compliance checklist
- Identify which equipment is in “other than dwelling units” and likely to be worked on energized.
- Confirm whether any service or feeder-supplied equipment is rated 1000A or more.
- Apply the required general warning labels (110.16(A)) where applicable.
- Add the additional arc-flash labels required by 110.16(B) for qualifying equipment.
- Document labeling dates and keep records consistent with your facility’s safety program.
Need help applying NEC 2023 changes?
If you’re unsure whether your gear qualifies under NEC 110.16(B), or you want to confirm you’re labeling the right
equipment the right way, it’s worth getting an experienced electrical contractor involved. A quick walkthrough can prevent costly
rework and help ensure your safety and compliance goals stay on track.
