आर्क फ़्लैश कैलकुलेटर

How this is calculated#

The tool estimates the incident energy of an arcing fault. It uses the IEEE 1584-2018 model. It can also run the 2002 model for older studies. IEEE 1584 is not an AS/NZS Standard, so the steps cite its clause only.

1. Model. You pick the 2018 or the 2002 model. The 2018 model asks for the electrode configuration and the equipment. The 2002 model asks if the equipment is enclosed and earthed (Cl 4).
2. Arcing current. The tool finds the arcing current at 600 V. It then corrects it to your voltage for the electrode gap.
3. Enclosure. It works the equivalent enclosure size. It applies the enclosure size correction factor.
4. Incident energy. It works the incident energy at the full arcing current. It uses your clearing time and working distance.
5. Reduced current. It applies an arcing current variation factor. It works the incident energy again at that lower current.
6. Result. The tool keeps the higher of the two passes. It gives the arc flash boundary and the PPE category.

Worked example#

• 400 V switchgear with a 20 kA bolted fault and a 0.2 s clearing time. The working distance is 455 mm. The tool gives an arcing current of 13.64 kA and an incident energy of 7.01 cal/cm². The boundary is 1,373.09 mm. The PPE category is 2.

Limits#

• The 2018 model covers 208 V to 15 kV. Above 15 kV the tool uses the Lee model, which is a different method.
• The reduced current pass uses the same clearing time. Enter its own time from the device curve.
• The tool takes your bolted fault current and clearing time as given. Get them from a fault level study and the device curve.
• The result is an estimate. It is not a label and it is not a safe-work permit.

See also: Arc flash basics, Incident energy at a 400 V switchboard and Arc flash label for a commercial main switchboard.