Thanks. I had someone ask me if I thought is was allowed by the NEC. I answered no. He said wrong. Yes it is. Nowhere in the NEC does it prohibit AL wire for residential branch circuits. I thought that was odd, given all of the issues with it.
It has never been prohibited by the code. There were a lot of issues with the old alloy aluminum 15 and 20 amp conductors.
For a short period of time in the mid 70s, the new alloy aluminum conductors in 10 and 12 AWG were on the market as single conductors. I don't think any NM was ever produced using the new alloy.
The contractor I was working for did an apartment complex in 74-75 using the single conductor aluminum conductors in sizes 10 and 12 AWG. We did the service work for that project and for some other similar projects built using copper conductors for many years. There were no more issues with the aluminum project than there were with the copper project.
It was cheaper, easier to install, and had no more problems than copper, but the product was only on the market in those conductor sizes for a few years as they could not overcome the bad reputation of the old aluminum that was problematic.
I believe there is copper clad aluminum in both NM and single conductors on the market at this time in those sizes, but I have never worked with it. As far as I know, there is no plain aluminum conductors on the market at this time in the 15 and 20 amp sizes.
