How to advance the accuracy of arc-flash studies by transitioning to the latest IEEE standards using ETAP

We upgraded an IEEE 1584-2002 study to the 2018 edition using ETAP, it significantly improved accuracy, strengthened confidence in the results, and enabled practical mitigation decisions.
Nick Bramhall, Director and Electrical Engineering Consultant, Safe Arc Solutions

When revisiting existing arc-flash studies, small differences in system configuration, short-circuit behaviour or protection timing can dramatically change results. This case study involved an arc flash study for a client using ETAP for power system modeling and arc flash analysis to identify a better alternative to the current approach, which used outdated methods and standards. The study focused on updates to equipment data, short circuit current validation, and it generated an entirely new set of Arc Flash results aligned with the latest IEC and IEEE standards, to provide the client with enhanced safety measures and confidence in their protocols.

Safe Arc Solutions is an electrical power systems consultancy with a strong focus on electrical safety and compliance. Based in Scotland, they work with clients across various industries and sectors across the UK, including oil & gas, manufacturing, and marine, to help address and simplify their electrical safety concerns. By offering practical solutions to the challenges of safely operating electrical power systems, including managing arc flash and conducting power system studies they help customers with site electrical safety, compliance, and procedures.

Location: Tillicoultry, Scotland, United Kingdom

Year: 2023

Ensure the safe operation of switchboards in compliance with IEEE standards

Challenges

1. Lack of confidence in legacy study results. The client’s previous arc-flash study (2009) produced incident energies exceeding available PPE, prompting delays to essential operations.

2. Outdated or incomplete system data. The earlier study relied on estimated short-circuit currents and assumed protection settings - two parameters that directly influence arcing current and clearing time.

3. Limited configuration analysis. Important operational scenarios such as transformer paralleling, motor contribution or alternate feeds were not evaluated.

4. Use of the older IEEE 1584-2002 method. The newer 2018 edition introduces major accuracy improvements based on thousands of additional laboratory tests.

Which solutions did they choose?

Why IEEE 1584-2018 Matters

IEEE 1584-2018 refines every part of the calculation process:
  • New electrode configurations, especially HCB (Horizontal Conductors in a Box), representing the worst-case for many metal-enclosed switchboards
  • Revised arcing current variation, producing more realistic predictions
  • Enclosure size correction factor, allowing each cubicle to be modelled according to its actual physical dimensions
  • Improved modelling of conductor gap, orientation and propagation geometry

Together, these advances deliver significantly higher accuracy when estimating incident energy and arc-flash boundaries.

 

Using ETAP to rebuild an accurate system model

Safe Arc Solutions created a detailed ETAP model using:
  • Verified short-circuit sources (grid, generators, large motors)
  • Updated protection settings from recent as-built documentation
  • IEC 60909 short-circuit calculations
  • STAR coordination analysis prior to arc-flash evaluation
  • ETAP’s Enclosure Editor to model realistic compartment geometries for 11 kV, 3.3 kV and 415 V MCC equipment
  • Accurate representation of incomers vs feeder cubicles and their differing electrode configurations
This complete model provided all required inputs for a validated IEEE 1584-2018 calculation.

What we delivered

Key results

1. High voltage switchboard (11 kV)

  • Minimal change in short-circuit current
  • Major increase in incident energy due to the adoption of HCB configuration

➡ Incident energy nearly doubled, revealing a previously underestimated hazard.

2. Low voltage MCC incomers (415 V)

  • Improved protection settings reduced clearance time

➡ Incident energy reduced from 78 cal/cm² to 51 cal/cm²

3. MCC feeders

  • Smaller enclosure sizes and VCBB/BCBB configurations applied

➡ Incident energy increased from 22 cal/cm² to 32 cal/cm², showing that the previous study underestimated risk.

4. Comparison across scenarios

Some locations saw increases, others saw decreases - highlighting that upgrading from IEEE 1584-2002 to 2018 does not systematically raise results but instead provides more realistic outcomes.

Outcomes

How ETAP enabled better mitigation

ETAP allowed Safe Arc Solutions to:
  • Visualise arcing current directly on TCC curves
  • Identify slow clearing times contributing to high incident energy
  • Optimise protection settings while maintaining discrimination
  • Quickly quantify the impact of proposed changes
  • Support actionable decisions using a validated, accurate model
One notable example reduced incident energy from 44 cal/cm² to just 3 cal/cm² by adjusting instantaneous pickup - verified instantly inside ETAP.

 

Conclusion

Transitioning arc-flash studies to the IEEE 1584-2018 edition provides a far more accurate understanding of risk. With ETAP, engineers can validate legacy studies, account for real-world system changes, and perform high-fidelity modelling of both high- and low-voltage equipment.
For Safe Arc Solutions and their client, ETAP delivered:
  • Significantly improved accuracy
  • Clearer insight into risk drivers
  • Practical mitigation strategies
  • Renewed confidence in operational safety



Videos

How to Advance Results Accuracy: Transitioning Arc Flash Studies to IEEE 1584-2018

Explore how outdated Arc Flash Study findings were overcome by utilizing ETAP software to update equipment data, validating short circuit currents, and generating fresh Arc Flash results aligned with the 2018 standard, providing the client with enhanced safety measures and confidence in their protocols.


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