The fundamental formula for the thermal short-circuit current capability of a conductor is expressed as:
) : The time it takes for protective devices to clear the fault. Engineering Significance
In simple terms, it provides the mathematical formula to answer this question:
The core feature for any IEC 949/60949 PDF tool is the calculation of the permissible short-circuit current using the formula iec 949 pdf
The standard details two main calculation methods for evaluating a cable's short-circuit capacity:
= A factor taking into account the heat dissipation into the surrounding components of the cable. The factor depends heavily on:
To truly appreciate the practical application, it's helpful to see it applied to a real cable. The following data is from an actual design calculation for a 132kV XLPE cable: The following data is from an actual design
Engineers utilize IEC 949 calculations primarily during the design, auditing, and upgrading phases of electrical infrastructure.
: The official source for IEC 60949:1988 and its amendments. iTeh Standards
| Related Standard | Full Title | Primary Purpose | | :--- | :--- | :--- | | | Selection and Erection of Wiring Systems | Current-carrying capacity & installation requirements | | IEC 60287 | Electric Cables - Calculation of the Current Rating | Thermal ampacity (load current) calculation | | IEC 60502 | Power Cables with Extruded Insulation | Construction & testing for LV/MV cables | | IEC 61443 | Short-circuit temperature limits (>30 kV) | Temperature limits for HV cables [7†L11-L14] | | IEC 60228 | Conductors of Insulated Cables | Conductor material & cross-section classes | These often contain corrupted files, outdated drafts from
Do not search for "IEC 949 pdf free download" on unverified websites. These often contain corrupted files, outdated drafts from the 1990s, or malware.
The formal, updated standard should be purchased from the or official national standards bodies (like BSI, DIN, IEEE). Official Purchase: IEC 60949:1988/AMD1:2008 Preview/Information: iTeh Standards
I=ε⋅IADcap I equals epsilon center dot cap I sub cap A cap D end-sub The standard provides distinct sub-formulas to calculate depending on the physical component configuration: Tubular metallic sheaths, tapes, and structural armor wires Critical Material Constants (