1 (IEC 61439-1) limit the temperature rise of copper busbar conductors to 105K, capping working temperature at 140°C. Exceeding this threshold risks annealing, reduced strength, insulation degradation, or even fire. (1) Heat Generation & Current-Carrying LimitsAccording to Joule's Law (Q = I²Rt), copper joints generate additional heat due to contact resistance. As the new energy sector continues its rapid evolution—from the powerful drive systems of electric vehicles to the stable energy hubs. Overheating occurs when the contact resistance at busbar joints exceeds acceptable limits. Below are the key contributors: 1. The key is to manage temperature rise and ensure the busbar's operating temperature does not exceed the limits of its material or, critically. The current rating is calculated from the conductor cross-sectional area, material (copper or aluminium), and maximum temperature rise per IEC 61439-1 (typically 70K above 35 degrees C ambient for bare copper). Short circuit withstand is verified using the adiabatic equation, ensuring the busbar. This executive summary introduces a rigorous approach to thermal modeling of temperature rise in high-current copper busbars (I2R, skin & proximity effects), targeted at engineers designing busbars, straps, and shunts. It lays out the scope, analysis goals, key equations, recommended modeling.
