While full, official copies require purchase, you can find detailed summaries and partial previews at these locations: IEC 60949:1988
: Material constant (e.g., 226 for Copper, 148 for Aluminum). : Initial and final temperature limits (°C). Iec 60949 Pdf Free Download
: Material-dependent temperature constant (e.g., 234.5 for Copper). Determine the Non-Adiabatic Factor ( While full, official copies require purchase, you can
IAD=K⋅St⋅ln(θf+βθi+β)cap I sub cap A cap D end-sub equals the fraction with numerator cap K center dot cap S and denominator the square root of t end-root end-fraction center dot the square root of l n open paren the fraction with numerator theta sub f plus beta and denominator theta sub i plus beta end-fraction close paren end-root : Cross-sectional area (mm²). : Duration of the short circuit (seconds). ): The final rated current is found by
I=IAD⋅εcap I equals cap I sub cap A cap D end-sub center dot epsilon Where to Access IEC 60949 Documents
): This assumes all heat generated by the fault remains within the conductor.
): The final rated current is found by multiplying the adiabatic current by the non-adiabatic factor.