Who’s Responsible for Arc Flash Warnings and Labeling?

An incident energy analysis by a licensed professional engineer provides a more accurate risk assessment for arc flash labels.

By: Derek Vigstol, Contributor

When the 2023 NFPA 70®: National Electrical Code® (NEC®) was adopted in jurisdictions around the country, there’s no doubt that electrical contractors had questions about how to apply the revision to 110.16(B). This is a little change with a big impact. Shifting from simply marking the service equipment with the voltage, available fault current, and clearing time of the service OCPD (overcurrent protective device) to a full on NFPA 70E® compliant equipment label forces a paradigm shift in how we aim to meet the purpose of both the NEC and NFPA 70E®: Standard for Electrical Safety in the Workplace®.

No doubt the first question that will come up is, “So, does this mean the Electrical Contractor (EC) has to perform an incident energy analysis for the facility?” And the answer here, in typical NFPA answer fashion: It depends! NFPA 70E permits one of two methods for determining the information on the label required by 130.5(H), either the Incident Energy Analysis Method, or the PPE Category Method.

An EC will be permitted to use either method to draft up a label to satisfy this requirement. This means that an EC could make labels containing PPE category numbers as a way to inform workers of the necessary arc flash PPE required in a given situation. However, this could prove to be problematic as we will find out here in a bit.


The next question that will eventually have to be asked is, “Does this place the liability for accuracy of this assessment on the shoulders of the EC that installs this label?” The answer to this question is not so easy to shell out. The way the system currently works is that the equipment owner is responsible for applying this label and carries the responsibility for the safety of those working on the equipment. By shifting this into the NEC, it changes the requirement for this label to take place as a condition of approval for the installation.

However, it still says in accordance with “applicable industry practice.” Therefore, the EC has the responsibility to make sure the label gets installed, but the equipment owner will still have the responsibility for the safety of those performing the work. Hmm, this raises an interesting hypothetical scenario: EC installs the label with inaccurate arc flash risk assessment information on it, worker gets injured when arc flash occurs while wearing the PPE determined by the label. Where does the liability fall here?

Unfortunately, I am not an attorney or a judge and cannot make that call for you, but I can say that this sounds like a nightmare to deal with when this happens. On one hand, the owner has the ultimate responsibility for safety within their facility. However, it is likely they would be able to seek retribution from the EC since it was the EC that provided the inaccurate assessment.

But the EC would likely have a claim that the owner should have verified the accuracy of the label prior to allowing the work to proceed. Or would this now be the job of the electrical inspector to assess the accuracy of the information on the label? As an EC, what can we do to make sure we don’t get ourselves mixed up in such a crazy liability merry-go-round?


First, the best way to ensure that our experience doesn’t go down this pathway is by making sure the information on the label is determined by a method that puts us at the least chance for being inaccurate. Of the two methods, one method (incident energy analysis) involves gathering essential data about the system and entering that data into a formula and software that will weigh items such as fault current, bus/electrode configuration, distance between bus/electrodes, and other important factors and attempts to estimate a range of what the potential incident energy will be during an arc flash. This formula is developed based on significant amounts of test cases that modeled the arc flash phenomenon to give a more accurate depiction.

The PPE Category Method is inherently flawed at best. The concept is that we take a given piece of equipment, set up a maximum amount of fault current that the system could supply at that point, set a maximum duration time for the upstream OCPD to clear an arcing fault, and put all the equipment under those parameters into a category of arc rated PPE that should provide protection to the worker.

The part where this method breaks down is in basing the parameters on items that are either difficult to figure out, like the clearing time of the upstream OCPD during an arcing fault, or are not the best measurement we could use. Max available fault current is tricky as a parameter because it then states that anything under that number is ok, but it is well established that lower levels of fault current could prove to take the OCPD longer to clear as they aren’t into the instantaneous trip range of the device. In other words, not ideal!


Back to the question of worker safety. If the EC wants to minimize the possible backlash from the labels they install, it really appears as though there is a clear winner in the method an EC would want to use here, incident energy analysis. However, most ECs don’t have the resources to do this in house just like most equipment owners don’t have the resources to do this on their own today.

The solution here is to involve a third-party organization such as an engineering firm or a consultant specializing in this form of arc flash risk assessment.  This shifts the liability pendulum back to something that resembles the way it is today. The EC still has the responsibility to ensure the label gets installed, the owner still has ultimate responsibility for the safety within the workplace, but a third-party expert in this sort of risk assessment process has minimized the chances that the information on the label is inaccurate and this is often backed by the stamp of a licensed professional engineer.

We can probably come up with about a million other potential “what if” scenarios but at the end of the day, there is no doubt in my mind that this change will elevate safety in the workplace. Will it take some adjusting to get used to? Sure it will. But so did the switch from rotary phones to touchtone phones, and now we have touchscreen phones! Don’t wait for this change to take effect before we start to figure out how to implement this into out process. We can start today by finding the best way to serve our customers and forge relationships that will help ensure the electrical contractor installs this necessary safety requirement in a manner that minimizes the potential for disaster. ESW

Derek Vigstol is an electrical safety and maintenance consultant for e-Hazard Management, LLC. He is also the co-host of e-Hazard’s electrical safety and maintenance focused podcast, Plugged into Safety, which can be found wherever you enjoy your podcast listening. He can be reached at derek.vigstol@e-hazard.com.

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