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An arc flash hazard study is an engineering analysis that calculates the incident energy (in cal/cm²) at each electrical equipment location and determines the required PPE category for workers performing energized electrical work. IEEE 1584-2018 ("IEEE Guide for Performing Arc Flash Hazard Calculations") is the current standard for arc flash incident energy calculations.
IEEE 1584-2018 updated the arc flash calculation methodology from the 2002 edition with empirical models derived from over 1,800 test cases. The new model accounts for equipment enclosure configuration (open air, MCC, switchgear, cable junction box), bus gap, electrode orientation (horizontal vs. vertical), and working distance. The 2018 model is more accurate — particularly for low-voltage systems below 600V where the 2002 model was conservative.
The arc flash study workflow: 1. Gather system data: transformer impedance, conductor sizes and lengths, protective device settings, and fault current at each bus. 2. Calculate available short-circuit current at each bus using the point-to-point method. 3. Calculate arc flash incident energy at each bus using IEEE 1584-2018 equations, accounting for the specific enclosure configuration and protective device clearing time. 4. Assign PPE category (1-4) based on incident energy: Category 1 (4 cal/cm²), Category 2 (8 cal/cm²), Category 3 (25 cal/cm²), Category 4 (40 cal/cm²). 5. Label equipment per NFPA 70E 130.5(H) or CEC Rule 2-306.
SparkShift's arc flash calculator implements the IEEE 1584-2018 simplified equations and the PPE table method from NFPA 70E Annex D. It generates results suitable for equipment labeling and incident energy documentation. For full studies on complex systems (multiple transformers, utility feed + generator, medium voltage), engage a licensed electrical engineer.
Open the arc flash calculator. Results include NEC citations and can be saved to a project for PDF export.
IEEE 1584-2018 provides empirical equations to calculate arc flash incident energy (cal/cm²) at electrical equipment based on system voltage, available fault current, equipment type, electrode orientation, and protective device clearing time.
The 2018 edition updated the calculation model with over 1,800 test cases, added enclosure configuration as a variable (open air, MCC, switchgear, cable junction), introduced electrode orientation factors, and improved accuracy for low-voltage systems below 600V where the 2002 model was significantly conservative.
8 cal/cm² corresponds to NFPA 70E PPE Category 2. Category 2 requires an arc-rated face shield (with balaclava), arc-rated jacket, arc-rated pants, heavy-duty leather gloves, leather footwear, and leather outer gloves. Minimum arc rating of 8 cal/cm².
SparkShift's arc flash calculator provides IEEE 1584-2018 incident energy estimates for individual equipment panels. A comprehensive facility-wide arc flash study — involving full system modeling, protective device coordination, and engineering documentation — should be performed by a licensed electrical engineer, especially for facilities with medium-voltage equipment or complex source configurations.
Disclaimer: SparkShift is a calculation tool for electricians and engineers. It is not a substitute for a professional power systems engineering study. SparkShift is not approved by NCEES, IEEE, NFPA, or any professional organization. For stamped engineering documents, engage a licensed Professional Engineer in your jurisdiction.