Overheating in electrical switchboards represents a critical challenge in ensuring the reliability and longevity of components.
Proper temperature management helps prevent premature aging of equipment and potential incidents. So, how can thermal dissipation be optimized to ensure the safety and efficiency of electrical installations ?
Electrical components generate heat mainly due to the Joule effect. This heat is dissipated in several ways:
Convection: Heat exchange between the surface of equipment and the internal air.
Conduction: Heat transfer through busbars and cables.
Radiation: Thermal exchange between equipment and the enclosure walls.
Electrical equipment must comply with the requirements of the IEC 60947 standard, validating their thermal characteristics. This standard evaluates equipment in a vertical position; however, in switchboards, circuit breakers are often installed horizontally, which alters their thermal behavior.
Partitions and reduced cable lengths also influence heat dissipation. Manufacturers must therefore optimize component integration to ensure optimal performance.
Low-voltage assemblies are evaluated according to 13 criteria, one of the most important being the overheating limit. This criterion measures each component’s ability to carry current while respecting thermal limits.
Even with IEC 61439 validation, performance can vary. The maximum permissible current depends on the enclosure design and the amount of copper used, as better thermal dissipation is often achieved with more massive conductors.
A high IP rating reduces the airflow required for natural cooling, thereby increasing internal temperatures. It is therefore crucial to select an appropriate IP rating from the design phase to avoid derating and to maintain panel compactness.
To improve energy efficiency, conductors and contacts must have minimal resistivity. A 0.1-ohm connection carrying 5,000 A dissipates 50 W, whereas a 0.2-ohm connection dissipates 200 W, increasing internal temperature and the energy consumption of air conditioning systems.
Effective management of overheating in electrical switchboards is essential to ensure durability and performance. By optimizing convection and conduction, and by carefully selecting the IP rating, it is possible to reduce the risk of overheating and improve the overall energy efficiency of installations.