
IEEE 1584, NFPA 70E and the “2-Second Arc Duration” Myth
IEEE 1584, NFPA 70E and the “2-Second Arc Duration” Myth Question: I’ve heard that an arc flash can’t last longer than two seconds. Is that true? Short answer: No. An arc flash can absolutely last longer than two seconds. Neither IEEE 1584 nor NFPA 70E says an arc flash is physically limited to two seconds. The two-second value is an assumption used for exposure time, not a limit on how long an arc can actually exist. This misunderstanding comes from












