Have you been to an aluminum pitch lately?
General Cable is making the rounds trying to rehabilitate aluminum again. They are still concentrating on feeder sized conductors but they do leave the door open for branch circuit sized wires sometime soon (10&12)
They blame it on device manufacturers who charge such a premium for Co/Alr

One interesting thing I heard is that if you really want to use NoAlox, you should be using it on your copper wire, not the aluminum (most lugs are aluminum) and they also say wire brushing the conductor is a waste of time.

It is an interesting show.

Sounds like a repeat of a presentation put on by the Southwire rep about 6 years ago.

Sure, it all sounds nice. I'm not convinced, though. Nor do I trust them- it all seems like they're setting the stage to bring back aluminum branch circuits.

Let me make my own position clear: I just want to do my job. I have to rely upon 'experts' to guide me. That's pretty hard to do when field lore conflicts with learned papers, or when one group of experts (the manufacturers) is at odds with another (the IAEI).

We've also all heard our share of whoppers over the years. The aluminum industry destroyed their credibility back in the 70's, when they made it an article of faith that every issue was the result of improper installation.

If it's that difficult to install properly, what's to keep the issues from arising again? Especially when their favorite installation defect - that anti-oxidant wasn't used- is now tossed aside. Now, they say, the goop isn't needed.

Theft? If you think thieves like copper, just wait until they discover there's aluminum out there!

Only used Alon rare occasions. If it was re-introduced for branch circuits, and I was still wearing tools, I would not use it.

I really have mixed emotions on this. It is clear the utilities are aluminum virtually 100% and they seem to be making it work.
I also lived with an aluminum house, my ex still has.
43 years later, she has had zero problems.

OTOH there are plenty of documented failures with binding screw terminal devices and aluminum wire so there is something going on there.

I do tend to agree, aluminum in an aluminum lug, should be fine.

Stranded aluminum seems to be pretty reliable except on overhead services where it's exposed to wind and rain. It weighs less and is easier to bend into the lug so the installation is easier. I wouldn't use it to save a couple hundred dollars but for a couple thousand it is on my favourite list.

Solid aluminum has a well known track record. I already learned that lesson.

I read the specs on an aluminum lug a few years ago and it was tinned so it could be used with copper. Are they all tinned?

Yes they are tin plated to avoid galvanic corrosion with copper. That was why he says you are better off using the anti oxidant on copper wire.
As long as the plating is solid, no problem but if you scratch up the lug installing the conductor, you might actually get more corrosion with the copper.

In my area we can win or lose a bid for as little as 50 dollars. That being said most of the new services I put in are aluminum, if aluminum branch conductors were to be available again there is no way I would install them! No amount of data from so called experts can cover experience in the field. We have all seen some prety hacked up copper installs that are still working fine, we still have miles of knob and tube in use around here, so copper is prety easy to install and make it work. Aluminum on the other hand, have to use anti-oxidant, have to use Co/Alr devices, have to use special connectors etc etc.... The choice is clear to me branch circuits will always be copper!

When I did the service on my house many years ago (over 20?), when it came time to do the service I ran AL wire because using CU wire would have costed me over $3,000 back then. Money that I didn't have. I did however install the underground service in PVC pipe. That way in case I had problems with the AL wire, I could pull it out and run new wires again.

Maybe they should be making their pitches to the insurance companies that don't like aluminum branch circuits.

To be clear, the pitch is for feeders, not 15 and 20a branch circuits. They are only talking about lugs, not binding screw terminals like you have on 15 and 20a devices.

The fundamental problem with aluminum conductors is that the metal is intrinsically softer than copper.

It's less forgiving when technique is bad -- and branch conductors are virtually certain to be reworked by DIYers -- who are all thumbs.

There's a strong tendency to forget just how much of our art is due to practice and 'touch.'

Hence, copper is propper.

It is not as much the softness as it is the difference in expansion rates. If the wire and the lug do not expand at the same rate, the contact open up, resistance increases, it gets hotter and the problem keeps getting worse until something burns up.

Greg:
Thanks for the info on 'only feeders' and not branch circuits.

I think a few of us had thoughts on Al NMC!

He was pretty specific that his pitch was just for lugs and larger wire. The talk about Al romex was just answering a question.

He did pass out samples of the old, bad 1350 alloy and the new AA8030. I can see it is a lot better. When you bend the 1350, it tends to kink and bend in one spot. The 8030 takes on a long arc.
The 1350 is really only designed for aerial lines, not something you will be bending a lot. It is pretty stiff.

The 1350 stuff they used in romex was annealed so it would bend easier but they still did not address the kinking problem. The "aluminum problem" was because they use steel screws in non-co/alr devices and the expansion rate is vastly different. The co/alr device has a screw that matched aluminum better, along with being bigger and I think there is some "bite" on the mating surface to grab the aluminum.
I still would not use it. We agree there.

About 8 years ago a colleague claimed we'd soon see Al branch circuits coming back. It hasn't happened, in fact quite the opposite is true, both Austria and Germany since removed the possibility from their regulations and upped the minimum size to 16 mm2 Al (branch circuits were 2.5 mm2 and up).

Here in the UK, we had a brief tangle with aluminium (or in your case, aluminum) branch circuit cables in the late 1960s. They were however "copperclad" conductors, with an aluminium core. It was, a very short lived type of cable and we went back solely to copper for such. I still find one or two houses with remnants of this and dread doing so. It is terrible to work with and the same problems as you had, with expansion happen all too often.
As in Germany and Austria, we now have a minimum size for this metal in cable, which is way above normal branch circuit sizes.

Al was introduced around the beginning of WWII here and dropped almost as soon as the war ended. By the late 1940s all electricians were back to copper. Therefore Al is fairly rare. Feeder-sized Al was re-introduced some time in the 1990s, usually 25 mm2 and up and mostly installed by utility companies rather than electricians.

Our neighbours behind the iron curtain used plenty of pure and copper-clad aluminium in all sizes, including even lacquered Al wire for transformers. Their Al conductors break easily when nicked but problems with expansion seem to be limited. Eastern Germany moved to crimp splices rather early, but in Hungary and Czechoslovakia mainly screw-type connectors were used for Al wire. I once had the chance to go through some old wiring in Prague checking all screws and the proportion of loose connections was no higher than in any copper installation I've encountered.

I really don't have a problem with AL conductors for 100A & larger feeders, & services, installed correctly it will give trouble free service, smaller then that no thank you.

Copper is still the conductor of choice,though.