VoltLab’s Transformer Short-Circuit Calculator

Field notes

The page combines an input form with its calculation model: transformer kVA, secondary voltage, impedance, phase, and fault type feed estimates for symmetrical current, fault MVA, peak current, and breaker kAIC. Its worked example uses a 1,000 kVA, 480 V transformer at 5.75% impedance and arrives at about 20.9 kA, then selects a 22 kA standard rating. The page explicitly excludes detailed source, feeder, motor, grounding, and arc-flash analysis.