Engineering calculator
Arc-flash screening (Lee method)
Conservative open-air incident energy estimate for initial screening only.
Inputs
Results
- Incident energy (screening)
- 113.8J/cm²
- Incident energy
- 27.2cal/cm²
E (J/cm²) = 2.142 × 10⁶ × V × Ibf × t / D² (V in kV, Ibf in kA, t in s, D in mm)
Safety-critical result — professional verification required
This is a screening estimate. It must not be used for design, equipment selection, protection settings or PPE without verification by a suitably qualified and competent engineer using a full study.
Assumptions
- Ralph Lee theoretical maximum-power model, open air
- Generally conservative at MV/HV; not intended for enclosed LV equipment
Limitations
- SCREENING ONLY — must not be used to select PPE or label equipment
- A full study to IEEE 1584 (or equivalent) by a qualified engineer is required
- Arc duration must reflect actual protection settings including breaker time
References: IEEE 1584 · NFPA 70E (reference)
Provided for general information. Gridlinks Solutions accepts no liability for decisions made using this calculator without independent engineering verification.
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