Figure 1: Arc Flash Hazard Default Data in the Library
The standard library stores some default data that is used in arc flash hazard calculations. For information on how to use the library, see EasyPower Device Library. This section provides an overview of the arc flash hazard section in the library.
Figure 1: Arc Flash Hazard Default Data in the Library
System kV (Line-Line): This is the line-to-line voltage of the system for which data is stored in the library.
Equipment Type: There are four different enclosure types—Switchgear, MCC/Panel, Open Air and Conductor.
NEMA Gap Unit: The unit in which the gap between phase conductors is specified. Units can be mm or inches.
NEMA Gap: Gap between phase conductors according to NEMA specifications for the voltage and equipment type.
Distance ‘X’ Factor: The incident energy at any distance is proportional to the power X of the inverse of the distance. In the expression (1/D)x, D is the distance in the appropriate unit and x is the distance factor.
IEC Gap Unit, IEC Gap and Distance ‘X’ Factor: Similar to NEMA equivalent.
The cells highlighted in yellow cannot be changed. You can edit the data in the white cells.
While performing arc flash hazard analysis, you can use the default clearing times in the library. To do so, you need to select the Predefined Fixed Times option in Bus Data.
Figure 2: User Clearing Times in Library Default
System kV (Line-Line): This is the line-to-line voltage of the system for which data is stored in the library.
Dev-1: The name of device function which is likely to be the first function to trip.
Time: The trip time for the device function for the column to the left.
You can specify a total of 4 device functions for each bus. The cells highlighted in yellow cannot be changed. You can edit the data in the white cells.
Note: We strongly recommend that arc flash calculations be performed using the actual protective device clearing times. This is automatic if you own EasyPower’s coordination program PowerProtectorä and have entered protective device data for each device.
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