← Electrical Systems Studio
🔥

Arc Flash Incident Energy

IEEE 1584-2018 · NFPA 70E · PPE Category

⚠️ Disclaimer: This calculator provides estimates for educational purposes using a simplified IEEE 1584 model. Do not use for actual arc flash labeling or PPE selection. A full arc flash study by a licensed engineer using IEEE 1584-2018 software (ETAP, SKM, EasyPower) is required for compliance with NFPA 70E and OSHA 1910.269.

When to use: Arc flash analysis is required by NFPA 70E for any energized electrical work. The analysis determines incident energy (cal/cm²) — the amount of thermal energy that could contact a worker at a given working distance. This determines the required PPE category and establishes the arc flash boundary (the distance where a worker would receive a 1.2 cal/cm² second-degree burn). Results must be posted on equipment labels per NFPA 70E 130.5.

System Parameters
Available fault current
kA
Breaker/fuse clearing time
ms
Conductor gap distance
mm
Typical: 60cm (480V panels)
cm
PPE Categories (NFPA 70E Table 130.5(G))
Cat 0: 01.2 cal/cm² — Arc-rated clothing, min 1.2 cal/cm²
Cat 1: 1.24 cal/cm² — Arc flash suit, min 4 cal/cm²
Cat 2: 48 cal/cm² — Arc flash suit, min 8 cal/cm²
Cat 3: 825 cal/cm² — Arc flash suit, min 25 cal/cm²
Cat 4: 2540 cal/cm² — Arc flash suit, min 40 cal/cm²
⚠ DANGER — Do Not Approach
3185.0
cal/cm²
Results
Incident Energy3185.0 cal/cm²
Arc Flash Boundary126.7 m
PPE CategoryCategory DANGER
Required PPEIncident energy > 40 cal/cm² — Do not work energized
Working Distance60 cm
Clearing Time100 ms
Key Mitigations
Reduce fault clearing time (faster breaker/fuse)
Increase working distance from equipment
Install current-limiting fuses
Use zone-selective interlocking (ZSI)
De-energize before working (LOTO)