NEC 240.67 Arc-Energy Reduction (Technical Paper)
Arc energy reduction is critical for electrical safety in the workplace. NEC 2011 introduced an Arc Energy Reduction requirement for circuit breakers (NEC 240.87) rated 1200 A and higher. The added circuit breaker requirement has reduced arc-flash injuries since being introduced by lowering fault clearing times. The value of 0.07 s for the new fuse clearing time requirement was chosen to align with circuit breakers using zone selective interlocking.
