Arc flash kills and maims electricians every year, and it’s still not taken seriously enough in the field. The energy released in an arc flash event can vaporize copper, cause third-degree burns from 10 feet away, and the pressure wave can knock you off a ladder. NFPA 70E is the standard that governs this - not the NEC - and if you’re working on energized electrical equipment above 50V, you need to know it.
The basics: before working on energized equipment, your employer is required to perform an arc flash risk assessment per NFPA 70E 130.5. This determines the incident energy at the working distance, establishes the arc flash boundary, and defines the PPE category required. PPE categories run 1-4 based on incident energy in cal/cm2. Standard work gloves and safety glasses are not PPE for arc flash. You need FR clothing, arc-rated face shield, and the full kit.
Here’s the thing that doesn’t get said enough: the best protection is de-energization. NFPA 70E 130.2 says you must justify energized work - it requires documented justification of why de-energizing isn’t feasible. “It’s inconvenient” isn’t justification. If you’re being told to work on live panels without arc flash PPE and without a written justification, that’s an OSHA violation and you have the right to refuse.