Supermetals Series: Part 3

Why Conductor Strength Matters in the Power Grid

Greg Olsen
November 19, 2024

In Part 3 of Copperweld's ongoing Supermetals Series, we will look at the challenges engineers currently face when designing grounding systems and how Copperweld CCS is capable of providing a unique solution.

The U.S. power grid is an intricate web of failsafes, carrying immense energy across vast landscapes — constantly tested by the unpredictable forces of nature and human behavior. In this high-stakes environment, the strength of grounding conductors is critical. Without reliable conductors to anchor and direct electrical surges safely to the ground, even the smallest vulnerability can escalate into major failures, threatening equipment, personnel, and public safety.
 
Many engineers are looking for solutions to address strength-related challenges and ensure the reliability of the grid. Broken, missing, or dislodged grounding conductors remain one of the biggest headaches for utilities worldwide. Without a continuous path to ground, electrical energy cannot be safely discharged. When faced with electrical surges or lightning strikes, compromised grounding systems fail to fulfill their crucial role in preventing disasters like equipment failure, electrical fires, and fatalities.

Copperweld’s Copper-Clad Steel (CCS) grounding conductors — known for their superior strength and a century-long track record of reliability — continue to prove their value as a grid-hardening solution capable of meeting today’s toughest power grid design challenges.

Conductor Strength Concerns

Utility Poles

Utility poles play an essential role in power distribution but face a wide range of grounding conductor challenges. With around 180 million utility poles across the U.S., each one represents a potential point of failure in the power grid.1 Their height—typically between 40 and 60 feet—makes them susceptible to wind-induced sway, which can strain and twist grounding conductors, eventually loosening connections to ground rods. At the ground level, conductors can be damaged by grounds maintenance and traffic accidents, while underground sections may be disrupted by shifting soil or impact. The easy accessibility of utility pole grounding wires also makes them prime targets for copper theft, further compromising grounding reliability. Addressing these vulnerabilities with high-strength options is crucial for maintaining the integrity of the power grid and ensuring a continuous path to ground.

Transmission Towers

Transmission towers are vital for transporting high-voltage electricity over long distances, but their sheer height and exposure to the elements make them particularly prone to grounding conductor issues. Overhead shield wire faces unique challenges, particularly in long spans between towers. These conductors must endure constant tension while withstanding environmental stresses like high winds, ice loading, and temperature fluctuations. The need for exceptional tensile strength and fatigue resistance is critical in these aerial applications, as any break or failure can compromise the continuity of grounding across multiple towers. Underground, soil shifting can lead to stretching, loosening, or even breaking of tower grounding or counterpoise conductors over time. Further increasing the risk of faults that could disrupt power supply and jeopardize the safety of maintenance crews, the remote locations of transmission towers can delay detection and repair of compromised grounding. Ensuring that these conductors possess sufficient durability is essential for maintaining reliable power transmission and overall grid safety.

Substation Ground Grids, Structures, and Equipment

Substation ground grids, structure grounding, and equipment grounding play a crucial role in preventing dangerous voltage gradients and minimizing the risk of electric shock by maintaining a near-zero potential throughout the substation. However, these conductors are susceptible to being compromised by underground soil movement and above-ground pressures that can exceed ten thousand pounds.  Compromised conductors can lead to overheating, equipment failure, or even catastrophic breakdowns of transformers and circuit breakers. These failures result in costly repairs, extended outages, and greater operational risks for utility providers. Ensuring that substation conductors are robust and resilient is vital for protecting personnel, maintaining equipment functionality, and supporting reliable power delivery.

Substation Fences and Gates

Substation fences and gates are essential for keeping the public and utility workers safe from high-voltage equipment. However, they are particularly vulnerable to damage and theft. When not properly grounded, these barriers can become live conductors during fault events, increasing the risk of transferring dangerous voltage to nearby areas and endangering personnel and passersby. Properly integrating fences and gates into the grounding system with high-strength conductors is vital to preventing step-and-touch potential injuries and ensuring perimeter safety.

Why Use Copper-Clad Steel (CCS) for Grounding?

Copperweld CCS grounding conductors combine the conductivity and corrosion resistance of copper with the strength of steel through a permanent metallurgical bond. Compared to solid copper, CCS grounding conductors offer superior break-load strength, greater fatigue endurance, reduced theft incentives, and longer service life.

Superior Break-load Strength

Table 1 and Figure 1 show recent test results that compare Copperweld’s 21% Low Carbon Steel CCS to solid copper wire. These tests demonstrate that even Copperweld’s lowest-strength CCS was an impressive 1.63x stronger. Copperweld’s 40% High Strength CCS conductors provide an impressive 3x added break-load strength over solid copper, making them ideal for utility applications where tensile strength is vital to service life. This increased strength provides crucial design flexibility for substation engineers and additional peace of mind for utilities.

Table 1: In this test, Copperweld's 21% CCS conductors were an average of 1.63x stronger than copper.

Figure 1: Century 19 No. 9, the equivalent for 4/0 Copper, was an average of 1.62x stronger.



Extended Service Life

With up to five times the flex-fatigue endurance of copper, CCS conductors can withstand bending, jerking, and vibration, making them suitable for areas experiencing frequent mechanical stress. Figure 2 illustrates recent testing that measured the flex-fatigue performance of Copperweld CCS and solid copper conductors.

Figure 2: Copperweld CCS samples were an impressive 5x stronger than the equivalent 6 AWG copper.


Stronger Connections

Over time, copper-to-copper grounding connections tend to loosen. In environments where repeated flexing and vibrations occur, small movements wiggle and soften connection points. Over-tightening never seems to fix the this problem. CCS’s annealed steel core allows connectors to 'bite down,' creating long-lasting connections that remain stable under harsh conditions for decades.

[Photo coming]

Hardened Against Theft

Copper theft is a widespread issue, especially with rising copper prices. CCS conductors have a lower street value and are extremely difficult to cut, reducing their appeal to thieves and protecting 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. These products lack the metallurgical bond that defines Copperweld’s CCS.

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.

Figure 3a: Competitor sample does not meet ASTM standard for copper thickness uniformity.
Figure 3b: Competitor's inter-diffusion layer has gaps that allow moisture to penetrate.
Figure 3c: Competitor sample shows signs of weak bonding after ASTM B510 torsion testing.


How to Verify Genuine Copperweld Products

To ensure you're using a high-quality CCS conductor, look for the Copperweld® branding on the reel wrap. Genuine Copperweld conductors provide the durability, strength, and corrosion resistance that have made them a trusted choice for over a century.

To learn more about Copperweld Power Grid products:
To make inquiries or place and order, contact Copperweld Sales:
View Sources
Share