Unlike the simpler adiabatic method, the full IEC 949 approach accounts for into surrounding materials like insulation or the cable sheath. IEC 60949:1988
While standard cable sizing focuses on continuous load carrying capacity, IEC 949 addresses the critical window—usually lasting less than five seconds—when a fault occurs and a massive surge of heat threatens to destroy cable insulation. Core Purpose of the Standard iec 949 pdf
The standard breaks down the calculation into two distinct stages: 1. The Adiabatic Basis Unlike the simpler adiabatic method, the full IEC
Preventing permanent damage to cable insulation during a fault. The Adiabatic Basis Preventing permanent damage to cable
Meeting international best practices for electrical installations.
Avoiding oversized cables by using more accurate "non-adiabatic" calculation methods when appropriate. The Calculation Methodology
The standard (now officially designated as IEC 60949 ) is the international benchmark for calculating the thermally permissible short-circuit currents for electrical cables.