During remodeling I have found some copper clad aluminum wire. If I recall correctly is all 12 gauge used for outlets. It is clearly labelled as CU clad aluminum on the jacket of the insulation.

I think this wire dates from the 70s or maybe 1980s. As far as I know there are no problems with these existing circuits.

Is this type of wire considered safe to use? And/or are there any code compliance issues?

I understand that pure aluminum wire had many issues but have the impression that the copper cladding was meant to improve on that or avoid the problems. But it also seems like CU-clad AL is no longer sold / in use (true?) which seems like a concern.

The CU-clad AL wire I have handled is noticeably softer than normal copper wire, and I think the issues with pure AL were due to mechanical connections failing. So this is another concern.

While I have the opportunity to potentially replace this wire I'd like to do so if it is prudent (or necessary).

3 Answers 3


Copper clad aluminum doesn't have the safety issues that aluminum wiring has for household branch circuits. The cladding was applied with a special manufacturing process and it's held up over time.

The NEC tables for aluminum wire sizing are also for copper clad aluminum, so larger gauge wire is required for a given ampacity than would be with copper. So although you don't have to do anything special with it, but keep in mind that you can't for example put a 20A breaker on a circuit with 12 AWG copper clad aluminum - you're limited to 15A.

I don't know if copper clad aluminum is available for power any more, I have not seen it. It's likely that it came and went due to economics. For a time copper was so much more expensive than aluminum it was worth making. Now, the savings using aluminum are not enough to offset the manufacturing cost.

There was some low grade network cable on the market recently that was copper clad aluminum. It had a high failure rate, but it's not clear that the cladding was properly applied, etc. It was sold with a counterfeit UL mark, clearly a fly by night product.

The only reason I could see to replace it now is the possibility it may make a future buyer nervous should some future inspector note on their report that aluminum wiring was found in the house.

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    If the walls are being opened up, and you could replace the copper clad aluminum with relatively little expense and trouble, you should consider it so you could say there was no aluminum wiring at all. How many circuits are involved? Probably I would consider replacing it, but would decide the copper clad aluminum was acceptable. Aug 23, 2018 at 12:23

AFIK copper clad aluminum is not associated with higher failure rates than pure copper. I have lived with aluminum wiring in branch circuits since 1970. In our tract house all the original branch circuits were aluminum NM 12 awg for the 15 A circuits and 10 awg for the 20 A circuits. I pigtailed the receptacles and switches in 1980 and we had no problems associated with aluminum. Probably you don't need to pigtail copper clad aluminum, but I would examine the connections for evidence of failure or problems.

My understanding is that the problems with aluminum are due to surface aluminum oxide and to bulk softness leading to bulk flow of aluminum away from screw clamps at receptacles. The second failure path could still be a problem with copper clad aluminum.

When I checked the panel (GE) in chasing down a hall light that was flickering I found that one neutral had long been loose at the neutral bar, was making a poor connection and had heated the wire, burned the insulation, and damaged the conductor. In all the 15 A branch circuits at the neutral bar the #12 aluminum was crushed down to practically foil. I pigtailed all the #12 and #10 neutrals at the neutral bar.


The problems with both AL & CU-clad AL were primarily caused by the coefficient of expansion of AL wire. When current flows through wire an it's terminals, heat is produced. Because of the high coefficient of expansion of AL wire, terminals are stressed when the conductor in the terminal expands. After sufficient number of expansions, the terminal becomes loose. Loose terminals cause arcs, which produced even more heat.

You can minimize the problem by using Ideal (purple) wirenuts and copper pigtails.

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    Were there problems with CU-clad AL though? Oct 20, 2021 at 14:29
  • This describes the problems many people had with improperly installed AL wiring, but it doesn't seem to address the question asked. If you'll spend a moment taking the tour, you'll note that we expect answers in the box labeled "Answer", not just commentary. Once you've got enough rep (it's only 50 points) you can add comments anywhere.
    – FreeMan
    Oct 20, 2021 at 17:47

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