How Stray Current Corrosion Damages Critical Infrastructure

Below all the hustle and bustle and screaming cab drivers in NYC rest over 7,400 miles of sewer pipelines. There are countless infrastructure systems in major cities, just like the Big Apple, including storage tanks, transit systems, utility networks, and industrial facilities. In all those cases, the risk of corrosion often goes unnoticed. When moisture, oxygen exposure, soil chemistry, and aging materials mix, electricity tends to flow to places where it’s not meant to.

Whenever stray current corrosion occurs, it damages infrastructure. Instead of taking decades through traditional corrosion, stray current corrosion accelerates metal loss. That is why some systems may fail prematurely, even when they appear well-maintained.

For anyone dealing with such issues, like municipalities or utility providers, it’s crucial to reduce liability and extend the usable lifespan of pipelines through cathodic protection. Otherwise, those stray electrical currents can damage far more than a small span of metal.

What Is Stray Current Corrosion?

Corrosion typically occurs when a metal loses material due to an electrochemical reaction in its environment. That is normal and can take decades to occur, depending on the underlying material, protection measures, and local environment.

Stray current corrosion is a bit different. When unintended electrical current leaves one pathway and travels through a nearby metallic system, it removes metal. This happens when the current exits one metal structure and reenters the surrounding environment. The result is hundreds to thousands of times more damage to systems than with standard galvanic or atmospheric corrosion.

One way to look at this difference is through corrosion. Traditional situations tend to affect a broader section of the infrastructure more uniformly. It’s easy to trace and measure because of that uniformity. Stray current corrosion tends to be more concentrated, leading to severe pitting and metal loss that fail faster and are harder to measure.

Why Stray Current Corrosion Is Becoming More Common

Fifty or more years ago, stray current corrosion wasn’t as big an issue as it is now. There are so many interconnected and parallel systems around industrial facilities, renewable energy installations, battery storage, EV charging, and utility corridors that it is far more common for a current to “jump” to another without proper grounding or protection.

Electrical systems can coexist with pipelines, storage tanks, water systems, and long-forgotten buried infrastructures. Any uncontrolled electrical pathway causes currents to seek alternative routes. All that metal is the perfect medium, as it’s nice and conductive, which leads to corrosion damage.

Real-World Example: Transit Systems and Pipeline Damage

A good example of why corrosion and soil degradation analysis are necessary to detect potential stray current corrosion is provided by electrified rail systems. Spaces like SEPTA in Philadelphia, Caltrain in San Francisco, or CTA in Chicago are all fair examples.

These direct current transit systems rely on return currents. When those return paths become inefficient, electric current escapes into the surrounding soil and buried infrastructure from decades of development and building construction. It’s pretty common for plans to “get lost” or not be fully compliant when filed with municipalities.

Any pipeline operations located near rail corridors, such as those cities, tend to experience accelerated corrosion from stray currents. That is why organizations such as the National Association of Corrosion Engineers (now AMPP) publish guidance, research, and processes to properly mitigate risk from stray current corrosion.

Even though these systems are well-maintained and frequently updated, the risk is apparent. The nearby infrastructure is simply too attractive a pathway for stray currents.

The Connection Between Cathodic Protection and Stray Current Corrosion

One of the most effective ways to reduce the risk of stray current corrosion is through cathodic protection. These are crucial because the applied current to protect pipelines and other metal assets ensures that stray current has a better pathway to travel.

The trick is to ensure that cathodic protection systems are properly designed, well-maintained, and adequately monitored. Working with an experienced team like ours at Dreiym Engineering is how you get that reassurance, including regular maintenance checks and remote monitoring to further lower risk.

In addition to designing a custom cathodic protection plan, forensic engineers with proper experience can also conduct corrosion and soil degradation analyses. That is how to better predict how current will travel through different soils based on:

• Soil resistivity
• Moisture content
• Chemical composition
• Chloride concentration
• Sulfate levels
• Seasonal environmental changes

The more you understand the factors in your operating environment, the better you can protect against stray current corrosion.

How Engineers Investigate Stray Current Corrosion

When suspicious corrosion patterns appear, even when two cathodic protection systems are too close together, a formal corrosion investigation occurs. Our team at Dreiym Engineering is often called in for such post-incident investigations.

Our role is to determine why the damage occurred, whether the system remains at risk, and which parties are liable. We will look at several specific systems and factors, including, but not limited to:

• Electrical potential measurements
• Current flow analysis
• Soil testing
• Coating evaluations
• Pipeline surveys
• Grounding system assessments
• Cathodic protection system reviews
• Historical operating data analysis

The goal is to identify current pathways, identify interference points, and determine whether environmental factors will continue to contribute to deterioration. The result of such an investigation is used to determine future maintenance and upgrade concerns, all the way to legal proceedings involving municipal accountability and insurance payouts for any damage.

Forensic engineering is essential whenever the infrastructure of any kind fails. It goes well beyond basic inspections by focusing on reconstructing what led up to the damage or failure. In stray current corrosion events, such expertise often reveals improper grounding, design errors, utility interactions, or previously unknown buried interference sources.

Protecting Critical Infrastructure from Future Damage

The good news is that most areas of the United States can prevent stray current corrosion if it’s identified early. When industrial sites and utility providers utilize better monitoring programs, electrical surveys, and cathodic protection assessments, it helps. Scheduling regular soil evaluations at different times of the year or after major weather events, such as a flood or a deep thaw, can also help.

No matter what, facilities that use long runs of pipeline, storage tanks, or other metal infrastructure should always do what is possible to identify nearby rail systems, utility corridors, industrial facilities, or high-voltage systems. The EIA shows the strongest four-year growth of electrical demand occurred recently and is likely to jump 25% by 2030 and 78% by 2050. The simple truth is that the risk of stray current corrosion is only going to get worse.

Working with teams like ours at Dreiym Engineering goes a long way to avoiding such damages. We offer over 30 years of experience, covering everything from corrosion and soil degradation analysis near shoreline facilities to cathodic protection design for local pipeline-dependent systems. We have licensed and certified experts on hand to help you get the solutions, management, and preventative information needed for greater overall reliability.

Contact Dreiym Engineering today, and let’s have a closer look at your pipelines and other metal-related systems so you can mitigate the risk of stray current corrosion now and in the future.