IEC 60909:1988

This standard is applicable to the calculation of short-circuit currents: -in low-voltage three-phase a.c. systems, -in high-voltage three-phase a.c. systems with nominal voltages up to 230 kV operating at nominal frequency (50 Hz or 60 Hz). This standardized procedure is given in such a form as to facilitate as far as possible its use by non-specialist engineers.