Electrical Conductivity: Copper Clad Steel vs. Pure Copper - Copper Clad Steel | Copper Clad Aluminum

The Fundamental Difference: Bulk vs. Surface Conductivity

The choice between Copper Clad Steel (CCS) and pure copper is a classic engineering trade-off between a homogeneous element and an optimized composite.

Pure Copper is the conductivity benchmark (~100% IACS), conducting efficiently through its entire cross-section at DC and low frequencies.

Copper Clad Steel has a high-strength steel core clad with a copper layer. Its overall DC conductivity (30-70% IACS) is lower than pure copper, but this changes dramatically at high frequencies.

The Game Changer: High Frequency and the Skin Effect

The skin effect causes AC current to concentrate near a conductor’s surface at high frequencies. The skin depth becomes incredibly small (e.g., ~0.0021 mm at 1 GHz).

This is the reason for the existence of Copper Clad Steel. At high frequencies, current flows almost entirely within the copper cladding. If the cladding is thicker than the skin depth, the high-frequency AC resistance of CCS can be nearly identical to that of a solid copper conductor. The steel core, carrying little current, provides immense mechanical strength at minimal electrical penalty.

Head-to-Head Comparison

The following table summarizes the key differences and trade-offs between the two materials across critical parameters.

Feature	Pure Copper	Copper Clad Steel	Practical Implication
DC / Low-Frequency Conductivity	Excellent (~100% IACS)	Good to Fair (30-70% IACS)	Both can use for power transmission, DC buses, and low-frequency magnetics.
High-Frequency AC Conductivity	Excellent	Comparable (when skin depth < cladding)	Its attenuation is less than that of copper coaxial cable (at frequencies above 5 MHz), and at frequencies above 1000 MHz, its attenuation is half that of copper wire. Under high-frequency influence, copper-clad steel wire radiates more power than pure copper wire.
Tensile Strength	Lower than 400 Mpa	1300 Mpa	Pure copper wires frequently break during construction and operation. The lifespan of pure copper wire is greatly reduced.
Weight (g/cm³)	8.9	7.9	The specific gravity of copper-clad steel with a conductivity of 40% is 8.20 g/cm³, and the specific gravity of copper-clad steel with a conductivity of 20% is 7.9 g/cm³.
Material Cost	High	Lower	The lifespan of pure copper wire is greatly reduced by 40%. Copper-clad steel with a copper content of 34.7% has a lower conductivity. It saves copper by using steel, thus saving costs and conserving scarce copper resources.

Application-Driven Conclusions

Where CCS Excels:

In RF and Microwave systems (coaxial cable center conductors, antenna elements, radials), CCS is often the optimal choice. It provides the necessary mechanical integrity (for installation tension, wind loading, ice) without sacrificing RF performance. Its use in premium coaxial cables up to millimeter-wave frequencies is a testament to this.

Where Pure Copper Excels:

In low-frequency power applications, high-current busbars, and audio equipment where current uses the full conductor cross-section, pure copper’s superior bulk conductivity minimizes energy loss and heating.

Summary: It’s About Optimization

Pure copper is the champion of absolute, bulk electrical conductivity. Use it where ultimate electrical efficiency is the sole priority.

Copper clad steel is the champion of optimized, application-specific performance. It strategically trades some bulk conductivity for exceptional strength, reduced weight, and lower cost, while preserving excellent surface conductivity at high frequencies. The choice is not about a “better” material, but about the better engineered solution for your specific electrical, mechanical, and economic requirements.