Arc Flash Hazard results of almost identical buses are significantly different although the fault currents and trip times are similar
Figure 1: Similar Buses with Different Results
If your arc flash standard is set to something other than IEEE 1584-2018, this can be due to differences in grounding. The Arc Flash Hazard Report above shows that BUS-4 is solidly grounded. Notice the “X” in the column Gnd. As per IEEE 1584-2002 equations, resistance grounded/ungrounded systems have higher incident energy than similar but solidly grounded systems. For details, see Determination of System Grounding.
Note: The IEEE 1584-2018 standard no longer includes grounding in its calculations.
