Arc Blast Calculator
System Voltage = 0.48
Equipment Type = 0
Conductor Gap =
Arc Duration =
System Type = 0
Bolted Fault Current =
Energy Exposure =
Flash Boundary =
Risk Category = 6
Calculates the arc flash boundary and incident energy exposure to determine the risk category for commonly used electrical systems. This calculator will also provide the recommended PPE for use when working on these systems. These calculations are based on NFPA 70E requirements and calculations from IEEE 1584.
- System Voltage: Voltage of the electrical system.
- Equipment Type: Type of equipment being used.
- Conductor Gap: Gap between conductors. Typical conductor gaps are 10-40 mm for open air, 32 mm for switchgear, 25 mm for MCCs and panelboards, and 13 mm for cables.
- Arc Duration: Clearing time for the overcurrent device that is being used. These times can be found in the manufacturer's specifications. Typical arc durations range from .03-2 seconds.
- System Type: Either Grounded or Ungrounded system.
- Bolted Fault Current: Available fault current, in kiloamperes, at the point where the work is to be performed. The available fault current can be found by using the [https://.../t/f559f004c9761f601165 | Fault Current] template.
- Energy Exposure: Possible energy exposure in cal/cm².
- Flash Boundary: Boundary of the flash.
- Risk Category: Category of risk associated with this project. Refer to the table below for recommended PPE.
Calculates the arc flash boundary and incident energy exposure to determine the risk category for a Motor Control Center operating with a 3∅, 480 volts grounded system where the arc duration is 0.167, the conductor gap is 32 and the bolted fault current is 50.
- System Voltage: 3∅, 480 volts
- Equipment Type: Motor Control Center
- Conductor Gap: 32 mm
- Arc Duration: 0.167 sec
- System Type: Grounded
- Bolted Fault Current: 50 kA
- Energy Exposure: 12.46 cal/cm²
- Flash Boundary: 74.56in
- Risk Category: 3
The energy exposure is 12.46 cal/cm², the flash boundary is 74.56in, and the risk factor is 3.
As noted in the table below, it is recommended that flame retardant coveralls over flame retardant shirt and pants, flash suit hood, ear canal inserts, V-rated and leather gloves, and leather work shoes be worn when entering the flash protection boundary.
Bolted Fault Current