"Either you didn't read what I wrote or you just don't want to listen. As for using aluminum today, you aren't allowed to. The risk of someone who is not trained or skilled as an electrician or an electrical engineer making what could eventually become a fatal mistake is too great."

That is exactly why it shouldn't have been recommended in times past. IF electrical enginners don't understand what is going on, do you think local inspectors have the training? Some people weren't thinking.


"Aluminum was useful because it was a cheaper than copper and in trained hands a satisfactory alternative. I think most or all high voltage feeders in use are aluminum. BTW, they use different alloys today which are much harder and therefore don't have the same shortcomings as those used in the old days. Aluminum is also light and strong, a major consideration for long runs of heavy overhead cables."

Since when is aluminum cheaper than copper? High voltage feeders etc. can use aluminum because of properly trained people and properly scheduled checks to prevent problems from developing. Alot different than commercial, such as bldg and houses which have virtually no checks once installed.

The problem, back then, with aluminum is that it didn't have "spring" like copper does. So once it gives, it doesn't spring back. Temp changes etc. will cause it to come loose from the connection.