Iec 949 Pdf

The original document, IEC 949 (1988) – "Calculation of thermally permissible short-circuit currents, taking into account non-adiabatic heating effects" – was officially renumbered as IEC 60949 in 1997.

It provides the mathematical formulas needed to calculate how much short-circuit current a conductor can safely carry for a specific duration (usually less than 5 seconds) without exceeding its maximum temperature limit. The History of the Naming iec 949 pdf

: Reciprocal of the temperature coefficient of resistance for the material at 0°C (K). Material Constants Reference The original document, IEC 949 (1988) – "Calculation

Details how to account for heat dissipation based on the duration of the fault. Material Constants Reference Details how to account for

IAD2⋅t=K2⋅S2⋅ln(θf+βθi+β)cap I sub cap A cap D end-sub squared center dot t equals cap K squared center dot cap S squared center dot l n open paren the fraction with numerator theta sub f plus beta and denominator theta sub i plus beta end-fraction close paren