When analyzing arc flash hazards in industrial power systems, I have encountered situations in which visual inspection reveals the manufacturer and the trip rating only. The breaker or fuse model cannot be determined from documentation or visual inspection.
Since the IEEE 1584 method of analyzing arc flash hazards depends on the protective device's response time--which varies according to the device's TCC curve--lacking the full product information poses a dilemma. Should the devices be modeled as switches and yield overly conservative results? Should the model information be guessed or assumed?
How should unidentifiable protective devices be represented in arc flash studies?