[villagetinker]

Originally Posted by Altavia

Because?

Much of the energy for a high frequency/rise time transient event is carried in the electric field around the wire. This is one of the reasons they use braided cable as it will present the minimum impedance to the event.

The UL approved aluminium cable is sized to handle the same transient currents as copper cable for lightening suppression applications.

As far as I know, there should be no electrical difference between these two for a properly installed system.

The key is 'properly installed', aluminum got a bad rep when it was allowed for house wiring and then it was not properly installed. I worked in the electrical power industry, and they use aluminum cable all the time with very specialized antioxidants and compression connections and even these fail occasionally. So I will agree with you if aluminum conductors are properly installed these would be acceptable, but my first preference would be copper.