Does Corrosion Impact the Performance of Copper-Clad Steel Wire?

CCS conductors are metallurgically bonded, combining the best properties of copper and steel. When manufactured using the correct processes and high-quality materials, CCS can surpass the service life of solid copper, even in cases where the steel core is exposed during installation.

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Compared to solid copper, CCS offers superior break-load strength, greater endurance, and remarkable resistance to corrosion. In fact, CCS conductors often outlast solid copper wire, even when exposed to the elements. CCS conductors have maintained a century-long reputation for durability.

CCS's added strength and resilience have helped engineers optimize power grids for decades. Still, some engineers seek reassurance that CCS is safe for buried applications.

In this article, we’ll address some of the most common corrosion-related questions about CCS.

Common Corrosion Concerns

1. What happens if the copper corrodes and exposes CCS’s steel core?

CCS conductors are designed so that the copper layer makes up most of the exposed surface area. This design puts the copper where it counts—on the outer surface, in contact with soil, air, and connectors. Copper, with its high conductivity and superior corrosion resistance, acts as a shield for the steel core.

While copper does oxidize and turn green over time, this patina actually enhances corrosion resistance, extending the lifespan of CCS. Special soil conditions, such as those containing cinder fill, can accelerate copper corrosion, but these cases are exceptions. In most environments, copper corrodes at an extremely slow rate.1, 2

According to “A Technical Report on the Service Life of Ground Rod Electrodes,” copper corrodes at a rate of only 0. inches per year in typical soil. At that rate, it would take 2,200 years to corrode through the 0.011-inch copper cladding on a Copperweld Century 19 No. 9 conductor!3

2. What if the steel is exposed due to impact or scraping? Will corrosion cause premature failure?

Even when steel is exposed, CCS can endure corrosion. In many installations, connectors such as exothermic or swage fully encase the cut ends of a conductor, protecting the exposed steel. However, when the steel is exposed due to improper termination or compromising the copper cladding, it forms a protective rust “scab,” which seals the steel from further corrosion.2

In worst-case scenarios, corrosion advances only a small distance—usually 2-3 times the diameter of the wire—before the rust scab halts further damage. Even when isolated corrosion occurs, the surrounding copper surface remains intact, maintaining conductivity across the length of the conductor. This is the same protective behavior observed in Copper-Clad Steel ground rods and tracer wire over decades of use. Of course, all conductors, including CCS and solid copper, should be handled with care to avoid damage during installation.2
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Lab and Field Testing

In the Lab

Copperweld conducted extensive testing from to to assess the effects of indentation and scraping/nicking on CCS conductors. The goal was to study the effects of exposed steel in underground applications.4
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After five years of burial in various soil conditions, the results were promising:

• Indented: Only 1 out of 50 samples that were indented to expose steel showed minimal corrosion after five years. The damage did not significantly affect the conductor’s performance. Notably, the force used to indent CCS far exceeded what would be required to sever solid copper wire.
• Scraped: In severely scraped/nicked samples, where the steel core was exposed, oxidation occurred and only proliferated at an expected rate. The conductor's electrical and mechanical properties remained stable.4
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In the Field

In , after 49 years of service in a Kentucky substation, Copperweld Century 7 No. 5 CCS conductors were unearthed. The conductors showed no evidence of corrosion beyond typical copper oxidation, and the copper cladding still met ASTM standards.

At the ends of the wires, corrosion formed the expected steel 'scab'. The copper layer remained intact, and there was no visible corrosion between the copper and steel interface.5
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Long-Term Studies

The National Bureau of Standards conducted a comprehensive underground corrosion study spanning over 45 years. This research, covering 37,000 specimens in 95 soil types, concluded that CCS conductors with 10-13 mils of copper cladding have an expected service life of 40 to 50 years. However, this estimate is conservative—Copperweld CCS products can often exceed these standards.2

Why Choose CCS Over Solid Copper?

While copper is often seen as the gold standard for grounding, Copper-Clad Steel offers several advantages that make it a better choice for many applications:

• Superior Strength: CCS conductors offer 2-3x the break-load strength of solid copper. This makes them ideal for power grid and utility applications where tensile strength is critical to preventing mechanical failure.
• Extended Service Life: With up to five times the flex-fatigue endurance of solid copper, CCS conductors are more resistant to bending, jerking, and vibration—making them perfect for applications that experience frequent mechanical stress.
• Secure Connections: CCS’s annealed steel core allows connectors to 'bite down', creating stronger, longer-lasting connections that remain stable for decades, even under harsh conditions.
• Reduced Theft Incentives: Copper theft is a significant issue, especially as copper prices rise. CCS wires, with their lower street value, are less attractive to thieves, offering additional protection for utility installations.

Not All CCS Conductors Are Created Equal

It’s important to note that not all CCS conductors meet the same standards. Inferior products from foreign competitors may fail prematurely due to cracks and gaps in the copper layer, which allow moisture to travel between the steel and copper layer. These products lack the metallurgical bond that defines Copperweld’s CCS.6

Copperweld’s proprietary bonding process ensures a seamless bond between the copper and steel, preventing moisture from penetrating the conductor and leading to galvanic corrosion. This is why Copperweld CCS consistently outperforms other CCS conductors and delivers reliable service for over 50 years.
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Contact us to discuss your requirements of Copper Clad Steel Wire. Our experienced sales team can help you identify the options that best suit your needs.

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