Busbar
The busbar''s material composition and cross-sectional size determine the maximum current it can safely carry. Busbars can have a cross-sectional area of as little as 10 square millimetres (0.016 sq in), but electrical substations may use metal tubes 50 millimetres (2.0 in) in diameter or more as busbars. Aluminium smelters use very large busbars to carry tens of thousands of amperes to the electrochemical cells that produce aluminium