These standards specify the parameters that should be considered when sizing busbars, including current rating, short-circuit withstand capacity, temperature rise, insulation, and environmental conditions. The correct sizing of a busbar is essential for several reasons. The International Electrotechnical Commission (IEC) issues globally accepted. Enter your system's parameters (e. Adjust the Safety Factor if needed (default is 25%). Click Calculate to see the required area and recommended size. Full IEC Verification Enter your base parameters as in the standard. The IEC 61439 standard applies to busbar assemblies that will be installed in electrical applications with a voltage rating up to 1000 V (for AC) and 1500 V (for DC).