How can equipment design impact arc flash hazards?
The incident energy exposure caused by an arc flash can be affected by the system configuration, system fault levels, and exposure time. System fault levels can be reduced by changing the system configuration to reduce available fault current, and by using current limiting devices such as fuses, breakers, and reactors. Using faster acting relays and trip devices can reduce arcing time or exposure time. A protective device coordination study should also be conducted to ensure proper device settings. Instantaneous relays could also improve clearing times limiting the arc exposure time. Fuse sizes should also be evaluated to determine if a smaller fuse could be used since smaller fuses reduce the exposure time.
