## Arc Flash Calculator

Calculation of arc flash incident energy and protection boundary in accordance with IEE Std. 1584 'IEEE Guide for Performing Arc-Flash Hazard Calculations'.

### System Details

 Title/Description:
 Voltage (kV):
 Bolted Three Phase Fault (kA):
 Arcing Time (s):
 Grounding: Grounded Ungrounded High Resistance

### Equipment Details

 Equipment Type: Open Air Switchgear MCC and Panels Cable
 Conductor Gap (mm):

### Arc Flash

 Distance to Person (mm):
 Protection Boundary Incident Energy (J/cm2):

 Distance factor, x:
 Arcing Current (kA):
 Incident Energy (J/cm2):
 Incident Energy (cal/cm2):
 Flash Protection Boundary (mm):

Tip: registered users can save calculations.

Calculate

## Symbols

V  -    system voltage (kV)
Ibf    -    bolted three phase fault current (kA)
Ia   -    arcing current (kA)
E   -    incident energy (J/cm2)
EB  - incident energy at boundary distance (J/cm2)
En  - normalized incident energy (J/cm2)\
t    -    arcing time (s)
D   - distance from arc to person (mm)
CB  - distance of boundary from arc point (mm)

## Notes:

1. EB can be set at 5.0 J/cm2 for bare skin or at the rating of any proposed PPE.
2. The limit of 5.0 J/cm2 is that at which a person is likely to receive second degree burns.
3. To convert J/cm2 to cal/cm2 multiply by 0.239

Gap and distance factors

Voltage (kV)

Equipment Type
Typical gap
between
conductors (mm)
Distance
factor,
0.208 - 1

Open Air  10-40  2.000
Switchgear  32  1.473
MCC and Panels  25  1.641
Cable  13  2.000
>1 - 5 Open Air  102  2.000
Switchgear  13-102  0.973
Cables  13  2.000
>5 -15 Open Air  13-153  2.000
Switchgear  153  0.973
Cables  13  2.000

For a more detailed explanation of the calculation, please see: Arc Flash Calculations Post

## Formulae

### Arcing current

System voltages under 1000 V:

Where:
K = -0.153 for open configurations and -0.097 for box configurations

System voltages above 1000 V:

Arcing current is then given by:

### Incident Energy

Normalized incident energy:

Where:
K1 = -0.792 for open configurations and -0.555 for boxed configurations
K2 = 0 for unground or high resistance ground systems and -0.113 for grounded systems
G  = the conductor gap (see table below)

Incident energy :

- for voltages less than 15 kV

Where:
Cf    = 1.0 for voltages greater than 1000 V and 1.0 for voltages less than 1000 V
x    = is a distance exponent from the table below

- for voltages greater than 15 kV

### Flash Protection Boundary

- for voltages less than 15 kV

- for voltages greater than 15 kV

Where:
Cf = 1.0 for voltages greater than 1000 V and 1.0 for voltages less than 1000 V
x = is a distance exponent from the table above