- Location
- Illinois
- Occupation
- retired electrician
The 15 and 20 amp aluminum that had all of the problems was a different alloy than what is used now.
I worked on a 125 unit apartment complex in 1975-76 that used the new alloy single conductor aluminum conductors as our local code requires EMT for more than 6 units. For a number of years after that I ran the service truck and there were no more problems with the aluminum project than others done in copper.
In addition to using the new alloy, all of the wiring devices wer CO/ALR. Those wiring devices have termination screws that much more closely match the thermal expansion and contraction than standard wiring devices. That mismatch of expansion and contraction between the conductor and the wiring device terminations was the major cause of the failures with the old aluminum. That issue, along with poor installation practices, is what results in the loose connection over time.
As far as I know the new alloy was never used for NM cable, and was only on the market as single conductors for a couple of years because of all of the problems that ocurred with the old aluminum NM.
