Calculation of the continuous current rating of cables (100 % load factor)

This technical document establishes a comprehensive framework for determining the continuous current rating of power cables under a loading factor of 100%. It provides detailed methodologies for calculating the thermal limits of conductors, taking into account various insulation types, installation conditions, and environmental factors. The approach described here accounts for the heat generation within the conductor and its dissipation through the surrounding insulation, bedding, sheath, and external medium. By utilizing specific formulae for steady-state temperatures, the standard enables engineers to assess the safe operating capacity of cables in different scenarios. It covers single-phase and multi-phase systems, addressing both AC and DC currents while considering skin and proximity effects. The calculation process incorporates data on thermal resistivity and specific heat capacities relevant to various materials. These guidelines assist in ensuring the reliability and longevity of electrical power transmission infrastructure by preventing overheating and potential failure. The document serves as a reference for designers and manufacturers to optimize cable selection and installation practices based on thermal performance criteria.