Busbar

Two metals are currently used as conductors in electrical panel boards: copper and aluminium. In particular, when needing to define the power distribution inside an electrical panel board, people mainly choose to use drawn bars, using both the above-mentioned metals. In configuring a bar distribution system, it is important to consider some electrical and mechanical parameters such as those listed below:

Electrical parameters: rated intensity value to carry based on the conductor cross-section and number, and the resulting voltage loss.

Mechanical parameters: bar size and number, based on the panel board dimensions and on their mechanical resistance.

Other factors to consider which might limit the passage of current through the selected conductors are linked to the working temperature of the conductor and to its capability to dissipate heat. In electricity, there is also a phenomenon called "skin effect" which determines the concentration of current on the conductor’s surface. The best conductor is therefore a flat one such as drawn bars in which the bar length and thickness ratio is the highest possible.

E.g. for the same cross-section and working temperature, a 100 x 5 mm bar carries 1.431 A, whereas the same cross-section, with 50 x 10 mm bar carries 1.129 A.