I'm trying to understand the real risk of using aluminum today, and conflicting and confusing information doesn't help. I have lots of questions and am not sure where to start.
I have gathered the old aluminum that caused all the problems was AA-1350, and the "new" stuff created in the 70s is the AA-8000 series. Also, I couldn't find the thread, but someone (iwire maybe) once made a comment that larger sizes of wire never had a problem. If so, what is considered the larger sizes. Did 8AWG connections for 30A dryers with the old aluminum have problems?
For the larger sizes, say 2AWG and larger for services, do people use antioxidant for all aluminum or just the old 1350. I find it odd the UL says it is based on the recommendation of the connector. Also, I think they say copper and aluminum are the same, which makes even less sense since aluminum oxide is a poor conductor compared with copper oxide. Someone said the 8000 series doesn't oxidize (one site I found says otherwise), which if true would also say applying antioxidant should be based on the wire and not the connector.
I hear that the 8000 series is just as good as copper, which again I don't believe with aluminum oxide being a poor conductor. If the statement is really 8000 series installed with antioxidant is as good as copper, I might accept that. But I also hear copper is more forgiving for a bad installation. That to me says copper is better. If an installation could be measured, a higher level is needed for aluminum to be acceptable. What is needed to make the installation of aluminum as good as typical copper installation (for a service lateral)?
I torque all my connections in a panel now, even the 14AWG. I always wonder how accurate does the torque need to be. One way that copper could be more forgiving is the torque spec is wider (I don't know what it is). If a lug says 50 in-lb, what is the real range of being a good permanent connection, both for copper and aluminum? Part of my concern is how accurate is the torque wrench being used. Just specifying 50 in-lb as a spec doesn't cut it, unless it is a minimum (which I don't think it is), since it is impossible to torque it to EXACTLY 50 in-lb.
Another thing, even if we can say the 8000 series aluminum is great and fixes the past problems, I find my suppliers only carry a few sizes that are 8000 series. I was surprised to find 1350 is not only readily available, it is the only thing available for some sizes. Related to this is the code doesn't say USE, RHH, and others have to the 8000 series. Does anyone know why it only requires it for certain insulations (and small conductors nobody makes
)?
I have gathered the old aluminum that caused all the problems was AA-1350, and the "new" stuff created in the 70s is the AA-8000 series. Also, I couldn't find the thread, but someone (iwire maybe) once made a comment that larger sizes of wire never had a problem. If so, what is considered the larger sizes. Did 8AWG connections for 30A dryers with the old aluminum have problems?
For the larger sizes, say 2AWG and larger for services, do people use antioxidant for all aluminum or just the old 1350. I find it odd the UL says it is based on the recommendation of the connector. Also, I think they say copper and aluminum are the same, which makes even less sense since aluminum oxide is a poor conductor compared with copper oxide. Someone said the 8000 series doesn't oxidize (one site I found says otherwise), which if true would also say applying antioxidant should be based on the wire and not the connector.
I hear that the 8000 series is just as good as copper, which again I don't believe with aluminum oxide being a poor conductor. If the statement is really 8000 series installed with antioxidant is as good as copper, I might accept that. But I also hear copper is more forgiving for a bad installation. That to me says copper is better. If an installation could be measured, a higher level is needed for aluminum to be acceptable. What is needed to make the installation of aluminum as good as typical copper installation (for a service lateral)?
I torque all my connections in a panel now, even the 14AWG. I always wonder how accurate does the torque need to be. One way that copper could be more forgiving is the torque spec is wider (I don't know what it is). If a lug says 50 in-lb, what is the real range of being a good permanent connection, both for copper and aluminum? Part of my concern is how accurate is the torque wrench being used. Just specifying 50 in-lb as a spec doesn't cut it, unless it is a minimum (which I don't think it is), since it is impossible to torque it to EXACTLY 50 in-lb.
Another thing, even if we can say the 8000 series aluminum is great and fixes the past problems, I find my suppliers only carry a few sizes that are 8000 series. I was surprised to find 1350 is not only readily available, it is the only thing available for some sizes. Related to this is the code doesn't say USE, RHH, and others have to the 8000 series. Does anyone know why it only requires it for certain insulations (and small conductors nobody makes
)?
