The horizontal busbars are placed at the top of the switchgear and/or at the bottom. They are connected with screwed joints between each cubicle unit, thus simplifying assembly, replacement and extension. In practice, good design is not only about ampacity. It also depends on material choice, joint quality. In low-voltage power distribution, the cabinet is never just a cabinet, and the busbar is never just a strip of copper. Behind every reliable low voltage switchgear lineup is a design balance that is harder than it first appears: current must flow safely, heat must be controlled, internal space. I agree that Rittal BmbH & Co. KG may process the personal data that I have provided above in order to send me information about system solutions relating to enclosures, power distribution, climate control and IT for marketing purposes. Current Carrying Capacity The bus bar must be sized to carry the continuous full-load current without exceeding permissible temperature rise limits.