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Prospective Fault Current at Point of Supply

Estimate the fault current at the end of a source and cable path using source fault level and entered cable impedance.

Inputs

Project inputs and assumptions

Range: 1–100,000 V

Use the system voltage basis consistent with the source fault-current data and selected fault-path model.

Range: 0.001–100,000 kA

Enter the verified symmetrical prospective fault current at the source point, in kA.

Range: 0–100,000 m

Enter the one-way route length from source to the point under review; the path factor represents the modeled fault loop.

Range: 0–100,000 Ω/km

Enter verified conductor resistance at the selected temperature, conductor and installation basis. Reactance is not modeled.

Range: 1–3

Use the factor appropriate to the modeled fault path, such as a line-and-return path. This is not a universal fault-type selector.

Result

Cable fault-path impedance (Ω)
0.03600
Estimated fault current (A)
7,692
Estimated fault current (kA)
7.692
Entered-source equivalent impedance (Ω)
0.01600
Result basis
This is a symmetrical fault-current estimate from the entered source and cable impedance model. Confirm fault type, reactance, temperature, protective-device duty and the applicable Australian requirements separately.

Formula

Calculation logic

Formula definitions and substituted values.

Before relying on the result

  • Estimate fault current after a feeder run
  • Compare source fault level with cable impedance effects
  • Use verified source fault data, conductor impedance, temperature and fault type; this is a symmetrical simplified estimate, not a switchgear rating study.

Related calculators

Use verified source fault data, conductor impedance, temperature and fault type; this is a symmetrical simplified estimate, not a switchgear rating study.