How do I calculate Short-Circuit Current (Ik) Calculation?

To calculate Short-Circuit Current (Ik) Calculation: Enter Transformer rating, Transformer impedance uk, Secondary voltage (L-L) and other values. Click Calculate. INDUGRID computes the result instantly using the formula: Ik = U_n / (√3 × Z_total) where Z_total = √(R_total² + X_total²). No registration required.

What units does the Short-Circuit Current (Ik) Calculation calculator use?

The Short-Circuit Current (Ik) Calculation calculator uses the following units: kVA, %, V, m, mm². SI units are used by default.

Is the Short-Circuit Current (Ik) Calculation calculator free?

Yes. The INDUGRID Short-Circuit Current (Ik) Calculation calculator is completely free, requires no account or login, and works on desktop and mobile browsers.

Electrical Engineering

Short-Circuit Current (Ik) Calculation

Estimate the prospective short-circuit current at a given point in the installation, considering transformer impedance and cable impedance.

Units:

in LinkedIn

💡All protection devices (MCBs, fuses, contactors) must have a breaking capacity higher than the prospective short-circuit current Ik at their installation point. Always verify with a full arc-flash hazard assessment for high-power systems.

Ik = U_n / (√3 × Z_total) where Z_total = √(R_total² + X_total²)

Input

Transformer rating iTransformer apparent power rating in kVA.

kVA

Transformer impedance uk iShort-circuit voltage of the transformer in %. Typically 4–6% for distribution transformers.

Secondary voltage (L-L) iTransformer secondary line voltage in Volts.

Cable length to fault point iLength of cable from transformer secondary to the fault point (one-way) in metres.

Cable cross-section iConductor cross-section of the cable in mm².

mm²

Result

Transformer impedance Z_T [mΩ] —

Cable impedance Z_C [mΩ] —

Total impedance Z_tot [mΩ] —

Short-circuit current Ik [kA] —

Minimum breaker breaking capacity [kA] —