Arc Flash Labels: What Goes on Each Panel
The 2026 National Electrical Code dropped the 1,000-amp threshold for arc flash labels, so far more switchboards, panels and control cabinets now need equipment-specific markings. Here's what a veteran EHS manager checks on each panel, and where a generic warning label still belongs.
I've walked a lot of electrical rooms with maintenance supervisors, and the labeling usually tells me how the program is doing. Faded stickers from the original install. A study done years ago with labels nobody updated after the transformer swap. A brand-new panel with nothing on it at all. Here's how I sort out what each piece of equipment really needs.
Two different jobs: warning labels and equipment labels
People use "arc flash label" for two different things, and mixing them up causes most of the confusion.
The first is a general warning label. It tells anyone who opens the door that there's an arc flash and shock hazard inside and that PPE is required. It doesn't change from panel to panel.
The second is an equipment-specific arc flash label. It carries numbers that come from an engineering analysis of that exact piece of equipment: the voltage, how far the arc flash boundary reaches, and either the incident energy or the PPE level a qualified worker needs. Those numbers can't be preprinted, because they depend on the available fault current and how fast the upstream protective device clears.
A preprinted label can do the first job well. It can't do the second, and anyone who tells you otherwise is selling you a problem.
What NFPA 70E says goes on the label
Under section 130.5(H) of NFPA 70E (2024 edition), equipment such as switchboards, panelboards, industrial control panels, meter socket enclosures and motor control centers, in other than dwelling units and likely to be examined, adjusted, serviced or maintained while energized, gets a label showing:
Nominal system voltage.
The arc flash boundary.
At least one of these: the available incident energy and its working distance, or the arc flash PPE category from the 70E tables (not both); the minimum arc rating of clothing; or a site-specific level of PPE.
The standard also says the data behind the label must be documented and reviewed at least every five years, the label gets updated when a change makes it inaccurate, it has to be durable enough for its environment, and the equipment owner is responsible for it. There's an exception for supervised industrial installations, where the information can be documented somewhere readily available instead of on the equipment.
What changed in the 2026 NEC
The National Electrical Code is the installation side of the house, and its arc flash rule got a real update. In the 2023 NEC, section 110.16 required a generic field-marked warning, plus a more detailed label only on service and feeder-supplied equipment rated 1,000 amps or more.
The 2026 edition combined those parts and dropped both the generic warning and the 1,000-amp threshold, as EC&M explains. According to the Minnesota Department of Labor and Industry's 2026 NEC FAQ, the marking now has to show the nominal system voltage, the arc flash boundary, the available incident energy or minimum required PPE, and the date the assessment was completed. That last item replaced the old "date the label was applied."
Two caveats from experience. The NEC only applies where your state or city has adopted that edition, and adoption varies. Minnesota's took effect August 17, 2026, for example. And it mainly governs new installations, so check with your local inspector about what applies to existing gear.
Where OSHA fits
OSHA hasn't adopted NFPA 70E as a regulation. In a 2006 letter of interpretation, the agency said it has no specific requirement for arc flash marking, but it pointed to two rules that do apply. 29 CFR 1910.303(e) requires equipment to carry its manufacturer and rating markings, durable enough for the environment. And 1910.335(b)(1) requires safety signs, symbols or tags to warn employees about electrical hazards, which the letter says includes arc flash. OSHA also treats 70E as evidence that arc flash is a recognized hazard and that protection is feasible.
If you want a refresher on why the header on that warning reads DANGER and not CAUTION, our signal word guide walks through it.
A panel-by-panel checklist
Here's how I'd label a typical commercial or plant electrical room.
Switchboards, panelboards, MCCs and control panels. These get the equipment-specific label from your arc flash risk assessment, printed by whoever did the study or by your team from its data. Put it where a qualified person sees it before opening the door. A general warning beside it doesn't hurt, especially on gear that unqualified people walk past every day. Our arc flash warning labels are ANSI Z535-style DANGER labels, ANSI compliant and OSHA compliant, that read "Arc Flash and Shock Hazard" and point workers to NFPA 70E PPE requirements. They're a supplement to the study label, never a substitute.
Disconnects. 1910.303(f) says each disconnecting means for motors and appliances, and each service, feeder and branch circuit at its disconnect or overcurrent device, must be legibly marked to indicate its purpose unless that's evident, and the marking must be durable. In an emergency, nobody should be guessing which switch kills the building. A plain main disconnect label makes the service disconnect obvious from the doorway.
Rooms with a mix of hazards. If you're outfitting a new room or a contractor's trailer, our electrical panel safety labels kit covers five common messages in one pack: arc flash hazard, disconnect identification, live parts, qualified personnel only and lockout/tagout. It's ANSI Z535-style, ANSI compliant and OSHA compliant.
The space in front of the panel. Working space is where I see the most citations waiting to happen. Under 1910.303(g)(1), the space must be at least as wide as the equipment or 30 inches, whichever is greater, let doors open at least 90 degrees, and run 3 to 4 feet deep depending on voltage and what's across from the equipment. And it "may not be used for storage."
Mark the floor and the panel so pallets, carts and holiday decorations don't drift in front of it. An OSHA-style electrical panel clearance label on the door gives supervisors something to point at.
Keep the labels honest
A wrong arc flash label is worse than none, because it tells a qualified worker the wrong PPE. Build these into your maintenance routine:
Re-check the study at least every five years, and any time you change a transformer, utility feed, breaker setting or fuse type.
Replace labels that are faded, peeling or painted over. Outdoor cabinets and hot mechanical rooms wear them out fastest.
Walk the room after every project. Contractors add panels and forget labels.
Don't let anyone hand-write numbers on a label.
The best arc flash protection is still not working hot. OSHA's electrical work-practice rules generally require deenergizing and locking out before work on or near live parts, and lockout/tagout landed at number 3 on OSHA's preliminary 2026 most-cited list, as our OSHA Top 10 breakdown covers.
You'll find more options for panels, switchgear and enclosures in our electrical hazard labels collection.
Before you order
Count your panels, disconnects and enclosures, and add spares for cabinets that get replaced. VLG labels are printed in house in Kenai, Alaska. They're Printed in the USA on premium low-shrinkage calendered vinyl with an industrial strength adhesive, so they stay put on painted steel, outdoor cabinets and warm switchgear.
Labeling a whole campus or a utility territory? Field crews can also browse our utility safety labels. We take bulk and custom orders, including site-specific wording. Minimums apply.
This article is general safety guidance, not legal advice. Arc flash labels with incident energy or PPE values must come from a qualified arc flash risk assessment. Check the current text of NFPA 70E, the edition of NFPA 70 (NEC) your jurisdiction has adopted, and 29 CFR 1910.303 and 1910.335, and consult a qualified electrical engineer or safety professional. State-plan states may have their own rules.
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