What Will This Cost Me?
Many people wonder how much an arc flash study costs. You may be one of those people.
It’s time to peel back the veil of mystery of an arc flash study a bit.
No, there are NO blood sacrifices, Ouija boards, or magic eight balls involved in determining the cost of an arc flash study.
There are, however, many factors that do play a role in determining the cost. These factors include things such as the size and type of facility, amount of electrical equipment, accessibility of equipment, and complexity of the system.
The thing that all of these items have in common is that they determine the amount of time the engineer will have to spend on a project doing the data gathering, modeling, and labeling.
Process of Doing an Arc Flash Study
The first step to starting an arc flash study is performing the data gathering. Once on site, the engineer will start working his or her way through the electrical system, doing things such as tracking down equipment, obtaining protective device data and settings, cable information, transformer nameplate data, motor data, and generator nameplate data.
This is where having up-to-date drawings can have a big effect on a project’s cost. Accurate drawings can drastically affect the amount of time on site required to track down equipment or determine where each is fed from.
The job for the engineer is not over once he or she leaves the facility. Next, the engineer enters the data collected during the walk-through of the facility in the modeling software.
When entering the data, the engineer creates a model of the system that is represented as a oneline drawing. It is during this time that the engineer will also be entering protective device information, transformer data, and setting up scenarios for running the arc flash study.
Once all of this has been done and scenarios have been run, the engineer will review the results and make note of any discrepancies. This usually leads to multiple iterations before the final product is achieved. Keep in mind that the study can be further complicated by the complexity of a system.
The final part of the process takes place when the engineer visits the site to apply labels. During this phase, the engineer will walk the site and place arc flash labels on all evaluated equipment. At the conclusion of the trip, the engineer will usually have a closeout meeting with the client, at which time the findings of the report will be discussed and hard copies of the report handed over.
Example 1 - Large Food Processing Facility
This project involved a large food processing plant with its own 115KV substation and medium voltage distribution loop that fed 12 padmount transformers. From there it was distributed out through 480V switchboards to a multitude of MCC’s and panelboards.
This original part of the facility had been in place for approximately 60-80 years, with multiple expansion projects taking place since then. The facility personnel had decent, if outdated, drawings with hand written notes on them.
With some help from facilities personnel, data gathering on this project ended up taking about fifteen days. Following the site visit, about five weeks was spent building and running the model. Labeling the equipment took seven days on site. This project ended up costing approximately $70K.
Example 2 - Small Multi-family Housing Development
This project involved a small multi-family housing development where an electrical contractor was performing a renovation. The system was comprised of one 208V, 800A panelboard that fed to two metering boards, and a few small house panels.
For this project, the electrical contractor provided all the required field data and documentation for the new equipment. The contractor also applied the arc flash labels. As this was a small system, with the majority of hours coming from modeling, the total hours ended up coming to just under two eight-hour work days. The total cost was just under $3,000.
Is That Cost Set in Stone?
If the figures above look intimidating, be assured that companies can do a lot to help reduce the cost of an arc flash study. Those facilities that have the following in place will have the most efficient, cost-effective study:
A good one-line diagram, meaning it is up-to-date and accurately represents the system
Layout drawings with accurate equipment locations
Their own electricians available to assist in gathering data
Updated equipment
Existing equipment that has been properly installed and maintained
Maintenance and Testing records for equipment (i.e. breakers, transformers, CT/PT’s, etc.)
Pay Now or Pay Later
Maybe the dollar amount looks steep to you now – a natural reaction from most clients at first. Consider, then, the potential cost of lack of knowledge – what you do not know can hurt you or those around you.
Electrical workers who do not know the hazards in their work area or what steps to take to mitigate the hazards can very well end up getting hurt. Once a shock or arc flash incident occurs, different costs accrue.
The numbers show that knowledge and implementation of that knowledge can cut costs drastically when compared to the cost of an electrical injury or electrocution (death) at the workplace. The cost of worker’s comp and possible ligation, along with company costs of damaged equipment and time lost from work, can add up to many times more than the costs of an arc flash study and subsequent training and audits.
Employers are required to provide a place of work that is free from hazards that can cause death or serious harm to workers. A key step to meeting this goal is to know the electrical hazards involved – which only an arc flash study can provide.
e-Hazard Can Help!
There’s no need to make a hasty decision. But make sure to find out the answers to your questions about the importance of having a current and accurate arc flash study at your facility.
The professionals at e-Hazard are happy to answer those questions! Contact us on the web at mailto:questions@e-hazard.com or call us at (502)709-7235.
Great article, John! There is a ton of misinformation out there about arc flash and coordination studies, costs, etc.. I always try to teach how important this information is when I visit a facility.
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what percent can cost the diferent steps in making arc flash study icluding gathering data nas one line diagram?
There is no real percentage. It depends on the system. Usually the data gathering and one-line development is the most costly part. Many companies have their workers gather data guided by an engineer and the engineer does the modeling.
I was a student in Mr. Hoagland’s class twice. I worked at a manufacturing plant and conducted an arc-flash risk assessment. I used Easypower software. Every piece of equipment was labeled. I retired about 5 years ago. I am a licensed electrical contractor. My previous employer asked me to conduct a 5-year reassessment of arc-flash safety.
My questions:
Do I need to redraw a new oneline, or can I use the previous drawing I drew?
Since I retired five years ago, do I need to re-examine all protective devices? I do not know what changes were made in the last five years.
Can I use previous and existing drawings without personally verifying their correctness, and physically verifying all the circuit protective devices?
Your reply will be highly appreciated.
Thank you
Sheel Pandey
Hi Sheel,
Thank you for your questions. At e-Hazard, we have performed reviews on arc flash studies conducted both by our own team and by others. Even when clients report that nothing has changed, our field verification process regularly uncovers new or modified equipment — often to the surprise of the facility staff. This is not uncommon, and it underscores why diligent data verification is non-negotiable.
Based on what you’re describing, this reassessment needs to include thorough field data verification. The good news is that if you have access to the original EasyPower model and files, your engineering time will be minimal if the system has indeed remained largely unchanged. Your previous one-line can serve as a guide during field verification — walking down the system against what’s documented. If verification confirms that the original one-line is still accurate, you may reuse it, but you should note the date on which it was field-verified.
To your specific questions:
1. Can you reuse the previous one-line? Yes, as a starting point and field reference, but not without verification first. It must accurately reflect current system conditions before any arc flash calculations can be considered valid.
2. Do you need to re-examine all protective devices? Yes, if safe to do so or under sound engineering judgement. NFPA 70E Section 130.5 requires the arc flash risk assessment to reflect the actual installed system. Protective device type, rating, settings, and condition directly affect incident energy results and arc flash boundaries. Since you cannot account for changes made during your absence, field verification of all protective devices is required for a defensible study. It was unclear whether the previous study was performed to IEEE1584-2002 or IEEE1584-2018, that may add an additional dynamic. Also, it is unclear whether the utility contribution was estimated, but that will likely require updating.
3. Can you use existing drawings without personally verifying them? No, not if you are conducting and certifying the reassessment. IEEE 1584-2018 requires accurate system data as a foundational input. You may get a person (that is trained, experienced, skilled, qualified, authorized, certified, knowledgeable, etc.) to perform the field verification on your behalf and use that data to update the EasyPower model.
One final note: we would recommend that arc flash engineering analysis be performed by, or under the direct supervision of, a licensed Professional Engineer with sound power systems experience. The scope of work you’re describing goes beyond electrical contracting and into engineering analysis. That distinction matters both for the quality of the study and for liability purposes.
Hope this helps, feel free to reach out with any follow-up questions. If you have specific questions, email works better than posting