Arc Flash Labels: What You Need to Know
By Brandon Smoak, Contributor
OSHA requires employers to ensure that each employee exposed to hazards from electric arcs wears personal protective equipment (PPE) with an arc rating greater than or equal to the estimated heat energy that could be released.  Taken at face value, this OSHA requirement seems straightforward; however, accomplishing this outcome requires successful implementation of a series of events linked together like a chain that all build on one another to achieve the desired safety outcome. If any link in the chain is broken, it is possible that an injury will occur; arc flash hazard labels are a crucial link in this chain. This article discusses fundamentals of arc flash labels, what type of information is presented on these labels, and how electrical workers should respond to this information when it’s encountered on the job.
What are arc flash labels and why are they needed?
Arc flash labels are an important tool in the safe-work process that communicate pertinent information about the risks associated with a particular piece of electrical equipment. They give electrical workers the information needed to protect themselves with appropriate PPE prior to beginning an electrical task. Additionally, labels help employers comply with OSHA 29CFR Paragraph (g)(2) of § 1926.960, which requires that the employer make a reasonable estimate of the heat energy to which an employee would be exposed if an arc were to occur. Labels can take numerous shapes and forms depending on the situation, but one example is provided below (Figure 1):
What type of information is presented on labels?
According to NFPA 70, article 130.5(H), the following (minimum) information shall be on the label:
- Nominal system voltage
- Arc flash boundary
- At least one of the following:
- Available incident energy and the corresponding working distance, or the arc flash PPE category level
- Minimum arc rating of clothing
- Site-specific level of PPE
See Figure 2, below, for an example label and a description of each area of the label:
- Incident Energy: the amount of energy on a surface at a specific distance from a flash; communicated in calories per sq. cm.
- Working Distance: the distance between the arc source and the worker’s face or chest.
- Arc flash boundary: the distance from exposed live parts within which a person could receive a 2nd degree burn.
- Insulating Glove Class: the class of rubber insulating gloves the employee shall wear.
- Arc-Rated and ‘Other’ PPE Requirements: indicates the personal protective equipment (PPE) required to prevent an incurable burn at the working distance specified during an arcing fault for the calculated amount of incident energy.
- Shock Hazard: bus voltage at the fault location
- Limited Approach Boundary: the only boundary that may be crossed by an unqualified person, when accompanied by a qualified person.
- Restricted Approach Boundary: the boundary that may only be crossed by a qualified person using adequate safety equipment and work techniques.
- Bus Name: fault location for bus report.
- Protective Device Name: the protective device that clears the arcing fault or portion of the total arc fault current.
- PPE Category: The minimum incident energy category rating of required PPE, in accordance with NFPA 70E – Table 130.7(C)(15)(C). The minimum rating of each category shall be above the calculated incident energy of the equipment in question. Note: Site specific requirements can require additional PPE protection levels than what is required in this table.
Where are they installed?
Arc flash labels should be installed in readily accessible locations on all equipment in an electrical system on which an electrical worker might need to perform “energized” work. Examples of such equipment include, but are not necessarily limited to, “switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers that are in other than dwelling units.” 
What action should be taken in response to these labels?
Worker interaction with arc flash hazard labels involves training (pre-encounter), understanding (encounter), and response (post-encounter prior to the commencement of work). Before a label is encountered, the employee “should be capable of reading and interpreting the information included on an arc flash hazard label.”  This capability is accomplished through sufficient employee-sponsored training and preparation. Additionally, before a label is encountered, an employer should have already provided the employee with sufficient PPE to be prepared for whatever maximum allowable exposure level he or she may encounter on the job.  Finally, with proper training (prior to the work) and knowledge of the associated risks (as communicated on the label), the employee must put on and use the appropriate PPE to mitigate the risks associated with the task at hand. 
In closing, arc flash hazard labels are an integral part of the electrical safety process. Considerable activity occurs prior to the creation of the labels in preparation to provide timely and accurate information to electrical workers when the need to safely perform energized electrical work arises. If inaccurate labels are provided or labels are misunderstood and the information presented is not applied properly, a serious electrical injury could result. It is therefore necessary for all participants in the electrical industry to continually reassess and improve their current understanding of this important link in the safety process to ensure a safe workplace for all involved. ESW
- National Fire Protection Association, NFPA 70E Handbook for Electrical Safety in the Workplace 2021
- OSHA 960(g)(2) Estimate of available heat energy
- OSHA 960(g)(5) Arc rating
- OSHA 335(a)(1)(i) Provision and use of PPE
Brandon Smoak is a consulting electrical and fire protection engineer with Total Arc Flash Safety, LLC, (TotalArcFlashSafety.com), an engineering firm focused on improving workplace safety and increasing the resiliency of complex electrical systems.