Aluminium vs. Copper Wire

Breaks easier, and can cause fires at high currents. It's difficult to terminate peoperly.

What type of wire and guage? Al can be crimped with the proper tooling like with solid wire crimps and dies, not the stuff you just crush with the plier looking tooling. I'd still use a deoxit type grease.

Soldering Al is a weird process, needs lots of scraping and a zinc bearing solder. No flux is needed.

AWG 20 dark brown wire. It looks just like copper wire, but cheaper, lighter and more flexible. I worry that it might break internally with repeated flexing.

Copper wire is pretty good copper. Aluminum is sold as alloys, some with rotten electrical conductivity. Numbers like 4:1 worse than pure copper.

No worries. It will break under repeated flexing. Probably your wire is copper coated aluminum. That is fairly common as it resolves the issues of soldering if not crimping. The problems with crimping or screw terminals is the different coefficients of expansion which ultimately loosens the joint. There are crimp connections that do not come loose, but they use specialized tools and crimps.

I ordered some copper wire from Ebay and got something one and a half AWG sizes smaller. I ordered two sizes up and again, got something 1.5 AWG sizes smaller. I repeated this a couple more times and they started shipping me Cu covered Al wires. Of course, I got a refund on every one but the first because I didn't inspect it in time to get the refund. Even though they are just in Maryland, ~100 miles from me, they never paid the return shipping to get it back. The insulation even has their name on it, so they can't claim they didn't know it w

Aluminum and copper coated aluminum were used widely in the 70s in the US. Many of them caused fires because they were not installed correctly. In the 90s there were many services which would crimp (properly) copper ends onto the aluminum wires so they could be used with conventional devices without risk of fire. I don't hear about this so much anymore.

Aluminum wire was used to install an after market heat pump in my father's house. The wires in the circuit panel became loose and fried the compressor. It was probably not a very efficient unit, but it ran for some 25 years before it was killed. Colman branded I believe. Now people tell me heat pumps seldom last 15 years. I think that is some malarkey. They are no different from refrigerators really. I've never had a fridge die other than to rust out. I've never had a heat pump last less than 20 years.

It looks like old copper (dark brown) wire inside. Solder does not stick to it.

I have three different sizes and stiffness AWG22 wires. Standard doesn't seem to help much.

Actually, Amazon or ebay will sell you solid plated "copper" wire, intended for jewelry making, that's stiff and not a very good conductor.

John Larkin wrote: ===============

** Large electros with screw terminals are sometimes linked using a metal bar to form pairs for plus/minus DC rails. The bar also often forms a ground or common in the device. Nickel plated copper is ideal for the job. But some think aluminium sheet or bar is just as good, even if less than 2mm thick. It's not.

..... Phil

Large-gage wires are almost always aluminum (500 mcm and up), and are terminated in hydraulic swaged copper-alloy lugs with a paste that prevents corrosion/degradation of the joints. It has been used extensively for many decades, but is not often found in house wiring because of its past problems, and building code restrictions.

Proper techniques are older than the 90s, I wired a bakery in the early 70s that used acceptable oxygen-free aluminum terminations.

My comments are for aluminum wire used in power wiring. Ed's #20 wire certainly isn't.

Aluminum wire is very common in larger sizes, including services for

200A and larger, gauge 1/0, and is not a problem.

Problems were for 15 and 20A branch circuits, #12 and 10. About 1965 copper prices spiked and aluminum started to be used in large quantities for 15 and 20A circuits. Problems ensued, like fires, and about 1971 UL removed the listing for aluminum wire and the aluminum rating for devices like switches, receptacles and wirenuts. New standards came out and the new switches and receptacles are marked CO/ALR. The new wire is harder, but the expansion is about the same. The vast majority of installed wire is the "old technology" stuff. UL tests are done with "new technology" wire, which is not what is mostly in the field. Use died out about 1973.

Aluminum wire has 2 major problems. One is high expansion rate. If it expands faster when loaded than the connection around it the wire can extrude making the connection looser on the next heat cycle. CO/ALR devices have better expansion characteristics, and harder wire helps.

The second problem is that aluminum is quite reactive, and a "clean" surface rapidly oxidizes. The oxide is very thin, but is an insulator. A wire nut may fail by oxide preventing wire-to-wire contact and the contact is through the cone shaped spring. A couple turns of the spring can become red hot. One fix is to abrade the wire to remove the oxide and apply an anti-oxide paste (like Noalox). AlumiConn connections are rated for aluminum (and copper) and appear to be good. Likely that crews dig through oxide.

I think these are like UK chock-a-block (sp?).

Large wires have a screw that cuts through the oxide, and installation often abrades and uses anti-oxide paste. Also connection may be made with barrel connections that are radially compressed onto the wire to form a cold weld. There was a COPALUM fix for small wires that did the same.

The CPSE contracted to have extensive testing (thousands of connections) of aluminum connections. The results are at:

The CPSC appeared to be headed for a recall. which would have been very expensive. In the inevitable court case aluminum wire was determined to not be a "consumer product" and thus not under the purview of the CPSC.

bud-- snipped-for-privacy@void.com wrote in news:pJ7DJ.282003$ snipped-for-privacy@fx98.iad:

Originally they declared that the deadly Beverly Hill Supper Club fire in Northern Kentucky was the result of faulty Aluminum wiring. It was later determined that such was not the case. In this instance.

Without anti-oxidant applied heavily, I would not use AL wiring. And would prefer copper.

Oh and I have wired up some pretty heavy duty industrial control panels and they ALL use copper, even on the feed lines. We are talking about some pretty big conductors and everything in 3 phase and cabinets over 8 feet tall and 18 feet long.

And a myriad of smaller cabinets with a lot of #8 in them. Again, all copper.

On a sunny day (Mon, 10 Jan 2022 12:05:19 -0800) it happened John Larkin <jlarkin@highland_atwork_technology.com> wrote in snipped-for-privacy@4ax.com:

I have seen a documentary about how that big A380 airplane is build. It says to save weight much of the wiring is alu. Must be reliable somehow :-)

What really hurts are the copper to aluminium joints however they are done. Power companies seem to manage it OK with big thick conductors but small signal stuff is skating on very thin ice.

Crimp joints on UK telcoms circuits from a particularly era when they briefly used cheaper aluminium cable cause a lot of trouble these days by partially rectifying ADSL broadband signals. BT management won't even admit to there still being any places afflicted with this problem.

Big problem with aluminium is the inert oxide surface layer. Fluxes that break through it can cause serious trouble and a solder formulation to wet out both is possible but I wouldn't want to rely on it.

Aluminium wire is of most use to flower arrangers.

A village close to me has a mix of copper and aluminium wiring between them and the exchange. A few lucky ones got 1Mbps but 256kbps was more typical. They were one of the first to start peer to peer microwave links as an alternative to their virtually useless landline services.