curl --request POST \
  --url https://api.iotools.cloud/v1/tool/arc-flash-boundary-estimator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "systemVoltage": "480",
  "faultCurrent": "20",
  "arcDuration": "0.2",
  "workingDistance": "455"
}
'

{
  "tool": "arc-flash-boundary-estimator",
  "tool_version": "1.0.2",
  "outputs": {
    "results": [
      {
        "quantity": "System voltage",
        "value": "480 V"
      },
      {
        "quantity": "Bolted fault current",
        "value": "20 kA"
      },
      {
        "quantity": "Arc duration (clearing time)",
        "value": "0.2 s"
      },
      {
        "quantity": "Working distance",
        "value": "455 mm"
      },
      {
        "quantity": "Incident energy at working distance",
        "value": "4.74795 cal/cm²"
      },
      {
        "quantity": "Arc flash boundary (1.2 cal/cm²)",
        "value": "905.053 mm (0.905053 m)"
      },
      {
        "quantity": "PPE category (simplified)",
        "value": "Category 2 — arc rating ≥ 8 cal/cm²"
      }
    ],
    "breakdown": "E (cal/cm²) = 2.142×10⁶ × V(kV) × I(kA) × t(s) / D(mm)² ÷ 4.184  (Lee method / IEEE 1584-2002 Annex D theoretical equation, open-air arc)\nV = 0.48 kV, I = 20 kA, t = 0.2 s, D = 455 mm\nE = 2.142e6 × 0.48 × 20 × 0.2 / 455² ÷ 4.184 = 4.74795 cal/cm²\nArc flash boundary = distance where E falls to 1.2 cal/cm² (curable-burn threshold) = 905.053 mm (0.905053 m)\nPPE category (simplified NFPA 70E cal/cm² bands): Category 2 — arc rating ≥ 8 cal/cm²\nTheoretical screening estimate only — not a substitute for a full IEEE 1584 arc-flash study with equipment class, gap, enclosure type and protective device coordination."
  },
  "credits_used": 5,
  "credits_remaining": null
}