⚠️ Simplified educational calculation. Uses a Ralph Lee / IEEE 1584 approximation — NOT engineering-grade. Real arc flash studies require the full IEEE 1584-2018 methodology with system-specific arc current variation, empirical constants, and up-to-date protective-device clearing times from time-current curves. Do NOT rely on this tool for actual PPE selection or arc-flash label warrant. Follow NFPA 70E / CSA Z462 tables + a licensed engineer for real work.