Copper-Clad Aluminum Wiring

Copper-clad aluminum (CCA) conductors are becoming a more common option as a wiring method in new construction. The primary reasons for this recent gain in popularity are lower cost and lighter weight. Many contractors are choosing to use CCA conductors for their branch circuit wiring supplies.

History of CCA

There is a misconception among many folks that this is a newly developed product. Copper-clad aluminum wiring was first introduced in the early 1970s. This was mainly brought about to counter the higher price and limited availability of copper.

CCA also provided a better solution to issues associated with solid aluminum conductors, like corrosion and thermal creep. The problems associated with solid aluminum conductors spiked the demand for CCA wire. 

The largest installations of CCA occurred from about 1972 until around 1977. After 1977, copper prices began to decline, and solid copper wiring continued to be the most dominant product.

CCA’s Comeback

The use of CCA remained basically non-existent for the next several years. The major wire manufacturers were not offering the product. In 2018, Copperweld introduced copper-clad aluminum NM-B cable. In 2022, they added CCA MC cable to their product list. 

Copperweld is the only American wire manufacturer of UL listed CCA NM-B cable at this time. They offer NM-B in wire sizes from 12 awg. to 4 awg. The 12-gauge and 10-gauge wires are solid and the larger sizes are stranded.

The 2026 edition of the NEC made a change in article 310.5(A) to allow 14 awg. copper-clad aluminum conductors. These will be 10-amp circuits, and receptacle outlets are not allowed. This change came about primarily because of lighter load demands associated with LED lighting circuits. Copperweld will begin to manufacture 14-gauge CCA NM-B cable to meet the needs of this change. The sheathing jacket on this cable will reportedly be in a teal color.

Physical Properties

Copper-clad aluminum wire is a “bi-metal” product. A thin layer of copper is bonded to the aluminum center core. 

This is a different manufacturing process from that of aluminum conductors, which include small amounts of other metals to form an “alloy.”

The copper coating on CCA is a minimum of 10% of the cross-sectional area of a solid conductor or each strand of a stranded conductor. The aluminum center core is made from the series AA-8000 alloy. 

What Home Inspectors Should Know 

There are a few ways to identify CCA. The sheathing jacket will be marked with the manufacturer’s name, the wire size, number of conductors, and the designation of CU-Clad or CU-Clad AL. 

One difference that may confuse inspectors is that the jacket is white on 12 awg., yellow on 10 awg., and orange on 8 awg. This differs from the colors associated with copper NM-B that inspectors are accustomed to. Another identifying clue is the physical size of the conductors where they terminate to the circuit breakers. We are normally accustomed to seeing 14-gauge on 15-amp breakers and 12-gauge and 10-gauge on 20- and 30-amp breakers respectively. CCA conductors are required to be larger than their copper counterparts because their ampacity ratings are less. A 12 awg. is the minimum size CCA conductor allowed for a 15-amp circuit. The ampacity ratings are the same as aluminum conductors.

The best way to identify CCA conductors is to look at the cut ends of the wires where they terminate to neutral and EGC bars in the panel. The aluminum center core can be seen when viewed at the cut ends.

Copper-clad aluminum conductors can terminate on any devices that are listed for copper conductors, which would be identified as CC, Cu, Cu/Al, and CO/ALR. Some manufacturers of appliances and equipment, like most electric water heaters and some HVAC equipment, will specify “copper conductors only.” In that case, CCA should not be used.

Some receptacle and switch terminals are rated only for 14-gauge and 12-gauge conductors to wrap the wire-binding screw. This normally applies to the cheaper devices. A 10-gauge wire attached to these devices would be incorrect. Better grade switches and receptacles typically are rated for 14-10-gauge wires.

Another possible mistake installers could make when using CCA would be to violate box fill requirements. Device boxes for receptacles and switches will often need to have larger cubic inch capacity to accommodate the larger conductors.

Ampacity Ratings

The ampacity ratings for CCA used for branch circuits are 10 amps for #14 (new provision), 15 amps for #12, 25 amps for #10, and 35 amps for #8. Although a #10 is rated for 25 amps, 25-amp breakers or fuses cannot be used for a branch circuit supplying general use receptacles because the overcurrent protection device cannot exceed the rating of the receptacle. The same would apply to a dryer circuit. The receptacle is rated for 30 amps, so the breaker cannot exceed that.

Conclusion

Some industry experts estimate that as many as one in five new construction homes in the US are being supplied with CCA wire, although regional popularity varies. With copper-clad aluminum wiring becoming more common in new residential installations, home inspectors must look closely when inspecting electrical panels and equipment to avoid misidentifying the predominant wiring methods.

Mike Twitty retired from a 17-year home inspection career in 2021. He is a licensed electrician and an ICC-certified electrical code compliance inspector for residential and commercial installations. Twitty currently stays busy providing continuing education for home inspectors focusing specifically on electrical subjects. Learn more at homescantraining.net or by emailing mtwitty2@hotmail.com. 

Opinions or statements of authors are solely their own and do not necessarily represent the opinions or positions of ASHI, its agents, or editors. Always check with your local governmental agency and independently verify for accuracy, completeness, and reliability.