why is aluminium used instead of copper for high voltage electrical cables????
Aluminum would only make sense in low current applications where cost and weight are important.
Aluminum is much cheaper and requires less structure to hold it up. It conducts very well. But is does not work well in homes because the expansion and contraction with heating loosens connections and those to copper wire need special wire nuts/grease
All of the earlier answers are correct and the first one is very good but nobody mentioned the fact that aluminium does not have much tensile strength, and that as a result of this, some high voltage aluminium cables have a steel cable in the centre to give them the required tensile strength. Aluminium bus-bars are very popular in low voltage work because they do not need to be flexible or possess much tensile strength but yet provide the benefits of being light and cheap.
Aluminium provies much better conductivity to weight ratio meaning copper is ofcourse the better conductor but it is also a lot heavier than aluminum aluminium is 2.74g/cm? and copper is 8.64 g/cm? soo copper is three times as heavier and if you used that in cables it would be reallly messed up and dangerous and costly as you would need better material or infrastructure to hold the copper wire in air compared to aluminium which is easy to hold in air and is less dense and would be suitable for electrical cables
