How the ETAP arc flash calculator helped detect critical errors in existing arc-flash studies

As the name indicates, the ETAP Arc Flash Calculator calculates many critical outputs of an Arc Flash study without building a simulation, assuming you already know all the inputs. Hence, it is an excellent tool for checking the accuracy of studies when you have a PDF and cannot open the source file. Moreover, it is also a fantastic tool for visualizing how changes in input and parameters can affect the Incident Energy and Arc Flash Boundary. It is the ETAP Arc Flash calculator.
By Thierry Epassa, Director of Electrical Engineering at Epassa Electrical Engineering Company

When reviewing more than 5,000 pages of arc-flash reports completed across 15 U.S. states - many already PE-stamped and labeled - Thierry Epassa, Director of Electrical Engineering at EEE Engineering LLC, uncovered severe calculation flaws. Using ETAP’s Arc Flash Calculator, he rapidly validated incident energy and arc-flash boundaries and exposed critical discrepancies caused by incorrect algorithms in another software package. This case study demonstrates how ETAP’s calculator provides immediate insight, accurate verification, and a clear understanding of how input parameters influence arc-flash results.

The EEEngineering LLC is a multi-state licensed engineering firm headquartered in Houston, Texas. They provide clients with deep expertise in electrical power studies, such as arc flash studies using the most current standards IEEE 1584 2018 and NFPA 70E 2021, load flow, reactive power, short circuit, protection, coordination studies, and other electrical calculations. They also perform all NERC studies and assist engineers with various troubleshooting issues related to power engineering.

Location: Houston, Texas, USA

Year: 2023

Ensuring high-quality Arc-Flash studies

Challenges

1. Reviewing reports without access to the source model. Many engineering firms validate studies by reading only the PDF results, often without the original simulation model - making verification nearly impossible.

2. Extremely long and complex reports. Arc-flash studies frequently exceed hundreds or even thousands of pages, creating a risk of overlooking critical inconsistencies.

3. Inability to hand-calculate key results. Unlike short-circuit currents or load-flow values, incident energy and arc-flash boundaries cannot realistically be hand-calculated, complicating independent review.

4. Limited technical background of some stakeholders. Safety or facility personnel may approve studies without the electrical expertise to question or validate results.

Which solutions did they choose?

Selected applications

EEE Engineering used the ETAP Arc Flash Calculator to:
  • Re-create incident energy and arc-flash boundary calculations directly from report tables
  • Validate whether the study’s outputs aligned with IEEE 1584-2018
  • Test how changes to equipment dimensions or parameters influence results
  • Identify systemic errors caused by outdated or incorrect algorithms in other software
ETAP calculations remained consistent with IEEE standards and correlated precisely with expected physical behavior.

Why do they use ETAP?

Main customer benefits

1. Rapid validation of arc-flash studies. ETAP provides accurate results without building a full model—ideal for reviewing external studies or verifying PDF-only reports.

2. Immediate detection of flawed assumptions. By reproducing calculations directly, inconsistencies become obvious. In this case, ETAP exposed major deviations caused by incorrect algorithm selection in the original software.

3. Clear visualization of how parameters influence risk. Interactive plots allow users to test variations in clearing time, working distance, enclosure dimensions, gap distance, and more.

4. Demonstration and educational value. Engineers can explain arc-flash concepts - such as the effect of increasing gap distance or decreasing working distance - through intuitive visual tools.

5. Confidence in IEEE 1584-2018 compliance. ETAP maintains the correct algorithm even when other tools revert unintentionally to legacy IEEE 1584-2002 methods.

6. Practical impact. Using ETAP, EEE Engineering identified incorrect labels, recalculated proper energies, and helped clients update their safety program with accurate, reliable information.

 

Conclusion

This case illustrates a fundamental principle:
Accurate input does not guarantee accurate output.

ETAP’s Arc Flash Calculator provides a reliable, standards-compliant method to independently validate arc-flash studies, detect hidden systemic flaws, and understand how each parameter affects incident energy and protection boundaries.
Equipped with ETAP, engineers can raise the quality of safety programs, ensure compliance, and confidently correct studies that may otherwise appear valid on paper.

What do they think about ETAP?

Customer perspectives

ETAP Arc Flash Calculator uncovered significant errors that were undetectable by reviewing PDFs alone.
Its accuracy and transparency made it the ideal tool to validate problematic studies.
By  Thierry Epassa, Director of Electrical Engineering, EEE Engineering

Even with correct data, you can still get the wrong results if the software uses the wrong algorithm.
ETAP allowed me to prove this instantly.
By  Thierry Epassa, Director of Electrical Engineering, EEE Engineering



Videos

How ETAP Arc Flash Calculator helped me detect significantly flawed arc-flash studies

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