Copper coated aluminum speaker wire?!

[Barrelhouse Solly]

I needed some zip cord for speakers. I looked on my local hardware store web sites and the internet retailer named after Wonder Woman's people. I noticed, after missing it for a bit, that more than half of the zip cord available was copper coated aluminum. I bought some copper wire. I'm wondering if it makes a difference with a 10' to 15' run. The saving on this amount of wire isn't consequential so I didn't worry about going for the copper. I was just surprised to see it.

 

[tineared]

Copper coated aluminum is less conductive than pure copper wire, so if you decide on the coated wire, be sure to buy thicker wire to compensate.
I only buy pure copper at 12 gauge thickness. It's generally overkill and covers any wire run to at least 60' (18m).

 

[DonH56]

I needed some zip cord for speakers. I looked on my local hardware store web sites and the internet retailer named after Wonder Woman's people. I noticed, after missing it for a bit, that more than half of the zip cord available was copper coated aluminum. I bought some copper wire. I'm wondering if it makes a difference with a 10' to 15' run. The saving on this amount of wire isn't consequential so I didn't worry about going for the copper. I was just surprised to see it.

For a short run it probably will not matter though I would buy the next even gauge up anyway (e.g. if you need 16 AWG, get 14 AWG). For longer runs you need to upsize a gauge or two to match the conductivity of pure copper. I prefer to avoid it because the copper layer is usually very thin, so wears off quickly (sometimes with the first connection), and copper/aluminum connections can degrade quickly due to dissimilar materials (e.g. special adapter pigtails are needed for Al house power connections to avoid fires).

 

[antcollinet]

I prefer to avoid it because the copper layer is usually very thin, so wears off quickly (sometimes with the first connection), and copper/aluminum connections can degrade quickly due to dissimilar materials (e.g. special adapter pigtails are needed for Al house power connections to avoid fires).

Exactly.

 

[SSS]

I needed some zip cord for speakers. I looked on my local hardware store web sites and the internet retailer named after Wonder Woman's people. I noticed, after missing it for a bit, that more than half of the zip cord available was copper coated aluminum. I bought some copper wire. I'm wondering if it makes a difference with a 10' to 15' run. The saving on this amount of wire isn't consequential so I didn't worry about going for the copper. I was just surprised to see it.

Another example which I found was for automobile jump start cables. Aluminum with copper skin. It seems just to reduce the material cost. Problem with aluminum is that when bending often it will break.

 

[kyuu]

(e.g. special adapter pigtails are needed for Al house power connections to avoid fires).

This isn't true nowadays. Aluminum is often used for larger gauge runs; all the higher amperage 240V circuits for appliances (and the EVSE) in my house (circa 2025) are aluminum wire. The only consideration, besides upsizing the gauge, is to make sure the receptacle is AL/CU rated. All breakers I've seen are AL/CU rated. Bus bars in the load center are often aluminum as well.

It's still a rarity to see aluminum used for regular 120V branch wiring, but I suspect that's because the price (and weight) difference for 12/14/16ga is too negligible to make it common practice. General antipathy to aluminum wire due to the widely-publicized issues with it the first time it was rolled out probably factor in as well. I imagine it also helps prevent less knowledgeable DIYers from doing bad things like using receptacles, wire nuts, etc. that aren't properly rated.

In regards to the OP's question, there's really nothing wrong with CCA as long as the gauge is upsized to account for the increased resistivity. But if you can get copper and the price difference is minimal, there's really no reason to do so at these wire sizes.

 

[jimmyjames8]

Aluminum wiring by current NEC must be AA-8000 alloy. Having said that, no electrical wholesaler I know or DIY big box store sells aluminum branch circuit wire (14/2 or 12/2 with ground).

 

[kyuu]

Aluminum wiring by current NEC must be AA-8000 alloy.

Yep, the alloy used was a big problem with the first attempt.

Having said that, no electrical wholesaler I know or DIY big box store sells aluminum branch circuit wire (14/2 or 12/2 with ground).

Indeed, seems to be exclusively reserved for larger gauges.

 

[DonH56]

This isn't true nowadays. Aluminum is often used for larger gauge runs; all the higher amperage 240V circuits for appliances (and the EVSE) in my house (circa 2025) are aluminum wire. The only consideration, besides upsizing the gauge, is to make sure the receptacle is AL/CU rated. All breakers I've seen are AL/CU rated. Bus bars in the load center are often aluminum as well.

For the service, a particular alloy is used, as mentioned by others, and the connectors also have to be a particular alloy series to be compatible. I imagine (not something I researched) most modern large appliances and service (breaker) panels use connections that are Al/Cu compatible. None of which obviates my concern about speaker cables IMO/IME.

It's still a rarity to see aluminum used for regular 120V branch wiring, but I suspect that's because the price (and weight) difference for 12/14/16ga is too negligible to make it common practice. General antipathy to aluminum wire due to the widely-publicized issues with it the first time it was rolled out probably factor in as well. I imagine it also helps prevent less knowledgeable DIYers from doing bad things like using receptacles, wire nuts, etc. that aren't properly rated.

The price of copper is making it a consideration for in-house runs in some areas, but then service pigtails are required if the original service (breaker panel) is not compatible (I've got to believe most are these days; ours is not) along with certified Al-compatible outlets, at least per our local code when I asked a few years ago during our basement remodel. Al or CCA wire was available, but special order, and not worth the effort for the savings. Our electrician had wired a house in Al and did not like it for a variety of reasons (mostly about it being harder to work with and more fragile in his experience). He showed me the wire, and it was 14 AWG Al (not CCA) that was lighter than copper but he said tended to break more easily and he had to ensure outlets and service met code. At that time (5-10 years ago) our code required pigtails; that may well have changed since then. We had our deck rebuilt last summer but the lights were not replaced so I did not review the current code. I was going to have them replaced, but got an outrageous bid, and then rather than do it myself went another route that did not require new outside wiring.

In regards to the OP's question, there's really nothing wrong with CCA as long as the gauge is upsized to account for the increased resistivity. But if you can get copper and the price difference is minimal, there's really no reason to do so at these wire sizes.

I'll stick with my old-fart out-of-touch desire to use copper for the reasons I stated above, mainly scraping through the thin copper layer pretty much on first or second use, and Al oxide is nonconductive and hard to clean off wires. (Copper oxide is also non-conductive but much easier to remove IME.) Now, I suppose someone will post a simple way to de-oxidize Al wires, since it is not something I have kept up with. When I last looked, the price difference for copper compared to CCA was significant, but for me it's a one-time buy and wire price is in the mud compared to the overall system cost.

 

[Salt]

CCA was reserved for voice coils to reduce mass, not cables, basically.
What has changed?

 

[Redacted]

Aluminium is abundant and cheap. Copper is increasingly expensive.
In the UK, at least, many years ago there was a cost saving made by supplying aluminium phone lines instead of copper - it was false economy.

Draw your own conclusions.

 

[Speedskater]

Aluminum wire used for AC power has to meet several close tolerance UL specs.
With Copper Clad Aluminum loudspeaker wire, it's anybody's guess as to true gauge and aluminum quality.