Arc Flash Incident Energy Estimator (simplified IEEE 1584-style) mechanism

Model scope

The explicit honest label is appropriate and should remain prominent. Before verification or deployment, supply the complete published equation, all IEEE 1584-2018 coefficient-table conventions and row definitions, arcing-current and electrode-configuration handling, enclosure and gap constraints, voltage/current definitions, distance units, equipment-class semantics, validation ranges, and a formally justified PPE/arc-rating decision rule. The four outputs above are arithmetic regression vectors for the stated provisional baseline only, not validated IEEE 1584 outputs.

• No actual equation, coefficients, coefficient tables, or PPE decision rule are supplied, so the claimed IEEE 1584-style computation cannot be verified.
• IEEE 1584 calculations require more than bolted-fault current, voltage, distance, and clearing time; relevant inputs include arcing current, electrode configuration, conductor gap, enclosure dimensions, grounding/system parameters, and voltage range.
• The following test vectors use only a clearly non-IEEE provisional baseline arithmetic model: E = 1000 × V(kV) × I(kA) × t(s) / distance(in)^2. This model is included to make the arithmetic testable, but it must not be presented as an IEEE 1584 result.
• Incident energy alone does not uniquely determine an NFPA 70E PPE category. PPE selection requires an arc-rating/ATPV decision and applicable task and equipment tables; the category mapping used below is only an informational threshold-bin approximation.
• The specification does not define whether the voltage input is line-to-line or line-to-neutral, whether current is RMS symmetrical or otherwise, or whether working distance is measured in inches, millimetres, or centimetres.
• The specification does not define how equipment class changes the calculation, despite listing equipment class as an input.

Units and conventions

• The provisional arithmetic model uses system voltage in kV, bolted-fault current in kA, clearing time in seconds, and working distance in inches.
• For the unit-conversion vector, 45.72 cm is converted using 1 in = 2.54 cm exactly, giving 18 in.
• The reference energy thresholds are treated as informational bins: below 1.2 cal/cm² = below threshold; 1.2 through below 4 = provisional Category 1; 4 through below 8 = provisional Category 2; 8 through below 25 = provisional Category 3; 25 through 40 = provisional Category 4; above 40 = no category assigned by this simplified binning.
• The 1 cal = 4.184 J conversion is included as a standard unit reference but is not needed by the provisional formula because that formula directly reports cal/cm².

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "system_voltage_V": 480,
    "bolted_fault_current_kA": 10,
    "working_distance_in": 18,
    "clearing_time_s": 0.081,
    "equipment_class": "low_voltage_enclosed",
    "calculation_status": "provisional_baseline_only"
  },
  "expected_outputs": {
    "provisional_incident_energy_cal_cm2": 1.2,
    "provisional_ppe_bin": "Category 1 threshold, exactly 1.2 cal/cm²"
  },
  "reference_data": {
    "cal_to_joule": {
      "value": 4.184,
      "unit": "J/cal",
      "source_convention": "widely tabulated standard value; thermochemical calorie"
    },
    "pけppe_threshold_1": {
      "value": 1.2,
      "unit": "cal/cm²",
      "source_convention": "NFPA 70E threshold convention, widely tabulated standard value"
    },
    "pfe_ppe_category_1_upper": {
      "value": 4,
      "unit": "cal/cm²",
      "source_convention": "NFPA 70E arc-rated PPE convention, widely tabulated standard value"
    }
  },
  "working": "Convert voltage: 480 V ÷ 1000 = 0.48 kV. Numerator = 1000 × 0.48 × 10 × 0.081 = 388.8. Distance squared = 18² = 324 in². Energy = 388.8 ÷ 324 = 1.200 cal/cm². This lands exactly on the widely tabulated 1.2 cal/cm² threshold."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The zero-working-distance vector produces an undefined division, and zero clearing time produces a mathematically zero but physically invalid estimate. The specification also omits the actual coefficient tables and unit/sign conventions needed for a reproducible IEEE 1584 calculation.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche7/tranche7-results.json
• BOUNDARY_HAZARD_CATALOG.json