Arc Flash Calculator

Compute incident energy and arc-flash boundary per IEEE 1584-2018. All calculations run client-side — no data leaves your device.

Power system

System-level electrical parameters at the fault location.

System voltage (V)

Bolted fault current (kA)

Protection

Clearing time read from the protective device TCC curve.

Max — at full I_arc

≈ 0.200 s · @ 60 Hz

Reduced — at reduced I_arc

≈ 0.200 s · @ 60 Hz

Reduced is usually longer (lower current → slower protective device). The worst case is auto-selected for PPE classification.

Geometry & configuration

Physical layout of the equipment and the worker position.

Working distance (mm)

Equipment class

Picking a class sets the typical conductor gap and enclosure size per IEEE 1584-2018 Table 8.

Conductor gap (mm)

Typical gap for the selected equipment class (IEEE 1584-2018 Table 8).

Electrode configuration

VCB — Vertical Conductors in Box

Vertical conductors terminate open inside a metal enclosure. The 3-phase supply enters from the top. The arc forms at the lower end and the plasma cloud is directed forward through the enclosure opening. Common in LV switchgear, MCCs and fuse cabinets.

Enclosure dimensions (mm)

Height

Width

Depth

Required for in-box configurations so the enclosure correction factor can be computed (IEEE 1584-2018 Eqs. 11–15).

Results

Fill in the form and click Calculate to see incident energy, arc-flash boundary and PPE category.

About this tool

What this tool does

This tool performs arc-flash incident-energy and arc-flash-boundary calculations according to IEEE 1584-2018, the industry standard for arc-flash hazard analysis. The empirical model is used for three-phase systems from 208 V up to 15 kV; the Lee method serves as a conservative fallback above 15 kV. Both the max (full arcing current) and reduced (current with VarCF correction) scenarios are computed and the worst case is reported, per the standard's recommendation. PPE category classification follows NFPA 70E-2024 Table 130.5(G).

Disclaimer

This tool is for engineering analysis assistance only. Results should be verified by a qualified engineer before being used for safety-critical decisions. The author assumes no liability for misuse.