Electrical Safety Stories Blog

Read the Signs: A Brief Look at Arc Flash Hazard Labels

Read the Signs: A Brief Look at Arc Flash Hazard Labels

By: Mike Enright


Every year OSHA announces its top ten violations, and every year, hazard communication sits near the top. While hazard communication violations are wide-ranging and impact everything from a slip-and-fall accident to chemical labeling to the topic we will be discussing today, arc flash labeling. Part of the much larger arc flash hazard analysis process, these labels are necessary in creating a safer work environment.

Labeling: An Important Part of an Arc Flash Risk Assessment

As we discussed in our last blog, the labeling process is one of the key components of an arc flash risk assessment. Whether completing a traditional incident energy analysis, using the reverse-study table method, or relying on PPE tables, labeling arc flash hazards is a necessary part of hazard communication.

Responsibility is on the Employer

Arc flash labeling is ultimately the responsibility of the employer, not the manufacturer or installer of the equipment. However, NEC 110.16 now allows for markings to be applied at the factory. This allowance does not replace a risk assessment and does not protect an employer from responsibility.

What Needs to be Labeled?

The NEC provides the following examples of electrical equipment that must be field marked with a warning label. This is not an all-inclusive list:

  • Switchboards
  • Panel boards
  • Motor control centers
  • Industrial control panels
  • Meter socket
  • Disconnect switches
  • Production line

Old Label, New Label

As arc flash risk assessments are only required to be performed every five years or in the event major modifications are made, workers may see labels compliant with the 2012, 2015, or 2018 standard of NFPA 70E. As the newest standard follows sets of tables (the reverse-study) method, the newest labels are more straightforward, only documenting Flash Protection Boundary, Flash Hazard Category, Incident Energy, Flash PPE, and Equipment ID. Old labels are still allowable if they are:

  • Still accurate
  • Complied with the requirements of the standard in effect when the labels were created
  • Have been completed within the last 5 years and no major changes have been made.

However, as the 2012 standard still includes the now defunct “Hazardous Risk Category (HRC)” information (removed in 2015), employers will need to train personnel on making compliant PPE decisions until labels are updated. While these labels do show the right information about incident energy, HRC is no longer a viable measurement.

Elements of an Arc Flash Safety Label

Depending on the standard that the labeling requirements follow or the software you use to determine risk and print labels, arc flash hazard labels will include some or all of the following information. Hazard labels are guided by ANSI Z535.4 2011, Product Safety Signs and Labels, with additional labeling requirements are also included in Article 110.16 of the 2014 version of the National Electric Code (NEC).

Signal Panel: Danger vs. Warning

The first thing you will see on an arc flash label is a “signal word,” used to identify the amount of potential damage and risk. Whether using “danger” or “warning,” the decision on which label to use must be consistent and documented. Caution (yellow) is noted as an option by some sources, but is unlikely.

Pursuant to ANSI Z535.4:

  • Signal words must precede the message panel.
  • The signal word panel must include a solid equilateral triangle that is the same color as the signal word.
  • The panel must include an exclamation point that is the same color as the panel background.
  • Signal words must be in all capital letters using a sans serif font, with the symbol and signal word positioned close together and centered in the panel.
  • Signal words in this panel should be larger than the message panel text. As a frame of reference, the size should be at least 50 percent greater than the height of the capital "H" in the majority of the text in the message panel.

For more information on label configuration, this article on ArcAD explored the ANSI Z535.4 technical details, providing more information about the labels themselves.

DANGER (White Text, Red Background; Red Exclamation Point, White Triangle)

Used only in imminently hazardous situations, the use of the danger sign indicates a situation which if not avoided will result in death or serious injury. The use of “danger” should be limited to the most extreme situations. NFPA does not specify a cutoff point for using the “DANGER” label, but these are often used when voltages exceed 600V if sufficient PPE is not available.

These labels are becoming less common, as ANSI has set forth a very narrow definition of when these are to be used. OSHA labels use a broader definition of “Danger,” but are becoming less frequently used, according to MySafetyLabels.

WARNING (Black Text, Orange Background, Orange Exclamation Point, Black Triangle)

The most common hazard label, the warning sign features orange background and black text. These are used to denote a hazardous situation that if not avoided could result in death or serious injury.

Optional Symbol Panel

In addition to the message panel displayed below, the addition of a relevant symbol to communicate the danger may provide additional warning to personnel about shock and arc flash hazards. These would include a matching color to the signal panel and easily understood symbols.

Message Panel: A Concise and Readily Understood Description of the Hazard

The next section of an arc flash label will document the hazard itself and appropriate measures of action or avoidance. Most commonly, the message used on an arc flash labels is “Arc Flash and Shock Hazard—Appropriate PPE Required.” The message should be safety black lettering on a safety white background.

A Note on New Arc Flash Hazard Labels under NFPA 70E (2018)

Under NFPA 70E (2018), the PPE portion now may receive more real estate on the label, and information may be more easily accessed. For instance, a compliant label may only include the following information:

  • Nominal system voltage
  • Arc flash boundary
  • At least one of the following:
    • Available incident energy and the corresponding working distance, or arc flash PPE category in Table 130.7 (C)(15)(A)(b) or Table 130.7(C)(15)(B) for the equipment, but not both.
    • Minimum arc rating of clothing.
    • Site-specific level of PPE.

To some degree, message panels may differ in layout but will include the following information:

Arc Flash Protection

One part of the panel will include information on arc flash dangers including boundaries, incident energy and working distance.

  • Incident Energy at Corresponding Working Distance: The Institute of Electrical and Electronics Engineers (IEEE) defines this as, “the dimension between the possible arc point and the head and body of the worker positioned in place to perform the assigned task.”
  • Minimum Arc Rating/Incident Energy: With the working distance noted, the warning label will also make note of the incident energy at this distance.
  • Arc Flash Boundary: Marks the shortest distance at which a person working at the time of an arc-flash may receive permanent injury (the onset of a second degree burn or worse) if not properly protected by appropriate PPE.

Shock Protection

The warning label will also include information about shock risk, boundaries, and appropriate PPE for addressing such risks. Among the elements noted:

  • Shock Risk: Discusses the voltage levels and could include the terms “shock hazard” and “shock hazard when cover is removed,” with other related terms discussing the voltage that could be released. May also appear in Arc Flash Hazard Protection portion of label.
  • Restricted Approach: Discusses the boundary in which a qualified individual may enter.
  • Limited Approach: Denotes the outer boundary in which a worker may be exposed to a shock hazard.

For more information on these boundaries, we invite you to read our blog, NFPA 70E: Understanding Approach and Arc Flash Boundaries.

Required PPE

The required PPE section notes the necessary PPE to protect from both shock and arc flash hazards, taking into consideration voltage and incident energy to denote glove class, hearing protection, eye protection, and arc resistant clothing. AR clothing decisions will rely on incident energy levels to determine the appropriate levels of PPE categories.

To learn more about PPE Categories, we invite you to read our blogs on the four classes of PPE and get to know our innovative 40 CAL AirLite™ Technology, a product offering Category 4 safety at a Category 2 weight.

Additional Information

Further, labels may include the following information about the equipment and the last inspection:

  • Date of Assessment: Notes the date the last hazard analysis was completed.
  • Equipment Information: Identifies the equipment.
  • Equipment Location: Building or facility location.

Protect Your Workers with Personal Protective Equipment from Enespro PPE

Hazard labels are one part of a much larger safety program. Necessary as part of a hazard and risk analysis, these labels will provide ample warning about the risks that could result from operating on equipment and explain the required PPE that will protect workers in the unfortunate event of an arc flash.

At Enespro PPE, we have designed a complete line of Arc Rated Personal Protective Equipment for different levels of exposure (CAT 1, 2, 3, 4), and offer Class 00, 0 and 2 rubber voltage rated glove & leather protector kits for your protection as well.

Learn more about our complete range of innovative electrical safety products and check out our blog for all of the latest Arc Flash safety news.

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