Calculate incident energy and arc flash boundary per IEEE 1584-2018 — determine PPE category and safe working distance.
| Step | Calculation | Result |
|---|---|---|
| 1 | Arcing current ratio from bolted fault current and system voltage | — |
| 2 | Incident energy at working distance using empirical IEEE 1584 or Lee method | — |
| 3 | Arc flash boundary (distance to 1.2 cal/cm²) | — |
| 4 | PPE category selection based on governing (higher) incident energy | — |
| Category | Minimum Arc Rating (cal/cm²) | Description |
|---|---|---|
| 0 | ≤1.2 | No PPE required |
| 1 | 4 | FR shirt + pants or FR coveralls |
| 2 | 8 | Minimum 8 cal/cm² AR/FR clothing |
| 3 | 25 | Minimum 25 cal/cm² AR/FR clothing + arc hood |
| 4 | 40 | Minimum 40 cal/cm² AR/FR clothing + multilayer arc hood |
| DANGER | >40 | Exceed Cat 4 — evaluate task hazard |