⚠️ Teaching tool only — not for PPE selection or arc-flash labels. Uses a simplified IEEE 1584-2002 / Ralph Lee approximation (superseded by IEEE 1584-2018, which requires regression constants not implemented here). Real arc-flash studies need: 1584-2018 methodology, system-specific arc-current variation, up-to-date protective-device clearing times from time-current curves, and sign-off by a qualified engineer. Energized work decisions must come from an engineered study or the task tables in NFPA 70E 2024 (US) / CSA Z462 2024 (Canada), never from a web calculator.