Short Circuit Current Calculator

Determine the maximum prospective fault current at a transformer LV secondary. Uses transformer impedance method per IEC 60909.

Short Circuit Current

Transformer Rating (kVA)

Secondary Voltage (V, Line-Line)

Transformer Impedance Z% (%)

Upstream Source Impedance (mΩ)

3-Phase Fault Current (Isc)13.88 kA

Symmetrical Isc (kA rms):13.88 kA

Peak Fault (×√2 × 1.02):20.03 kA

Transformer Z (mΩ):—

Total Impedance (mΩ):—

Fault Level (MVA):—

Formula UsedIsc = kVA / (√3 × V × Z%/100)