A Detailed Approach for ARC Flash Sustainability for Systems at or Below 240V and Over 2000A

The IEEE Std. 1584-2018 IEEE Guide for Performing Arc Flash Hazard Calculations has seen a welcome improvement in calculation accuracy from the 2002 version. Empirical data used for the 2018 standard shows that below 250VAC certain arcs sustained while other arcs failed to sustain. The '<240V and <125kVA transformer' exception in the 2002 standard has been replaced by '≤240V (nominal) and <2000A (short-circuit current)' language, that includes a band of arcs that did not sustain during practical testing. Previously published papers suggested further research into this area, however, within the finite resources available to the 1584-2018 working committee, not all requests could materialize. This paper investigates whether guidelines for arc sustainability (<250VAC equipment) match the empirical arc testing data available from IEEE, the Electric Power Research Institute (EPRI), and others while considering new developments and a better understating of arc physics. It uses recent data from studies performed at utilities and industry to determine the impact (if any) of a range of conservatism in the standard. This paper concludes by presenting a more detailed approach using NFPA 70E®-2021 for users who may be affected by conservative results and suggests areas where additional testing and research may benefit end-users.