Short-Circuit Fault Current Estimator (simplified) implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t5-091

Effect

Computation or source lookup only

Input and validation requirements

A zero-percent-impedance input causes division by zero and must be rejected. The convention probe also exposes a large result discrepancy: 7216.87836487032 A for a three-phase 480 V line-to-line interpretation versus 12500 A for a single-phase interpretation.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "transformer_kVA": 100,
    "percent_impedance": 5,
    "secondary_voltage_VLL_V": 480,
    "added_cable_impedance_ohm_per_phase": 0
  },
  "expected_outputs": {
    "rated_current_A": 120.28,
    "transformer_impedance_ohm_per_phase": 0.1152,
    "total_source_impedance_ohm_per_phase": 0.1152,
    "available_symmetrical_fault_current_A": 2405.7
  },
  "working": "Zbase=480²/(100×1000)=230400/100000=2.304 ohm. Ztr=(5/100)×2.304=0.05×2.304=0.1152 ohm. Zsource=0.1152+0=0.1152 ohm. Irated=100000/(1.73205×480)=100000/831.384=120.28 A. Isc=480/(1.73205×0.1152)=480/0.199526=2405.7 A."
}

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-tranche5/tranche5-results.json