When you’re sourcing structural steel products, understanding their practical properties isn’t just about spec sheets—it’s about ensuring your project runs smoothly, avoids unplanned costs, and delivers long-term reliability. As a supplier of MS (Mild Steel) Flat Bars, I get asked all the time about their electrical conductivity, a property that makes or breaks their use in everything from building foundations to electrical enclosures, fencing, and agricultural equipment. Unlike more specialized steel products, MS Flat Bars balance affordability, workability, and functionality, but their conductivity is often misunderstood compared to other steel variants. Let me break down what makes MS Flat Bar’s electrical conductivity unique, how it stacks up against similar products, and why that matters for your next project.
First, let’s ground this in what MS Flat Bar actually is. MS Flat Bar is a low-carbon steel product, with a carbon content usually between 0.05% and 0.25%—that’s what makes it “mild,” meaning it’s ductile, easy to cut, weld, and form, without being too brittle. Electrical conductivity in metals works on a simple principle: the more free, moving electrons a material has, the better it conducts electricity. Pure metals like copper and silver have extremely high conductivity because their atomic structure lets electrons flow unimpeded. Steel, however, is an alloy of iron with added carbon (and sometimes tiny traces of other elements), which introduces impurities that disrupt electron flow. That’s why all steels have lower conductivity than pure copper, but their exact numbers vary a lot based on their composition.
So where does MS Flat Bar land on this scale? I often tell customers that MS Flat Bar has an electrical conductivity of approximately 7–14% of the International Annealed Copper Standard (IACS), the global benchmark for conductivity (100% IACS = pure annealed copper). For context, ordinary steel plates—wait, let me clarify that, because “ordinary steel” here is another term for low-carbon, mild steel similar to our MS Flat Bar. If you check the details on Ordinary Steel Plates, you’ll see they have almost identical carbon content and alloying elements to standard MS Flat Bars, so their conductivity is almost the same, right around 8–12% IACS. That consistency is a big selling point for projects that need predictable performance, like grounding systems, where you need uniform conductivity across all structural steel components.
It’s important to pause here and note that conductivity isn’t the only electrical property that matters for steel. Resistivity, the inverse of conductivity, is often more useful for engineers calculating power loss in electrical components. For MS Flat Bar, resistivity ranges from 1.2 × 10⁻⁷ ohm-meters to 1.8 × 10⁻⁷ ohm-meters at room temperature. Compare that to stainless steel plate, which has a much higher resistivity (around 7 × 10⁻⁷ to 12 × 10⁻⁷ ohm-meters) because of its high chromium and nickel content. That’s why stainless steel isn’t ideal for electrical wiring or grounding rods—its conductivity is roughly a third of MS Flat Bar’s, so it would waste more energy and resist current flow. I regularly get requests from fabricators who initially considered stainless steel for electrical enclosures, only to switch to MS Flat Bar after realizing they needed the better conductivity for grounding to prevent static buildup or electrical faults.
Another factor that affects MS Flat Bar’s conductivity is its surface condition and processing. When MS Flat Bar is produced, it often has a thin layer of mill scale on the surface—this is a byproduct of hot rolling, made of iron oxides, which are electrical insulators. If you leave mill scale intact, it can reduce effective conductivity by up to 10% at the surface, because electrons have to cross an insulating layer to flow through the steel. That’s why I always recommend that customers who are using MS Flat Bar for electrical applications (like grounding or bus bars) have the surface pickled, blasted, or coated with a conductive primer. Even a thin, uniform layer of zinc (like the kind found on galvanized steel sheet for the structure) works surprisingly well, because zinc is a good conductor and creates a barrier against corrosion. Wait, let’s test that logic: if you use galvanized MS Flat Bar, does the zinc coating add to conductivity? In thin layers, the main current will still flow through the steel core, since zinc’s conductivity is about 27% IACS, which is higher than steel, but the core is thicker. So galvanized MS Flat Bar is still a great choice for outdoor structural projects that also need mild conductivity for lightning protection, for example.
Now, how does MS Flat Bar stack up against other specialized steels? Let’s take austenitic ferrite steel plate, which is a dual-phase steel often used for heavy industrial equipment. Its conductivity is around 5–8% IACS, lower than MS Flat Bar, because the dual-phase structure and higher alloying elements slow electron flow. Ferritic steel plate, another common structural steel with high chromium content, has even lower conductivity, around 3–6% IACS, making it less suitable for electrical applications. The difference in conductivity between these steels isn’t just a technical detail—it translates directly to performance. For a farm installing a new fence with integrated electrical shock for livestock, MS Flat Bar’s conductivity means the electric charge flows evenly along the entire length, rather than dropping off at intervals. For a commercial building’s grounding grid, MS Flat Bar’s consistent conductivity means every part of the grid will carry fault current safely to the earth, reducing the risk of electrical damage or shock.
One common misconception I run into is that all steel has the same conductivity, regardless of type. That’s simply not true. Carbon content is the biggest factor in steel’s conductivity: as carbon increases, conductivity decreases, because carbon atoms disrupt the iron’s crystal lattice, making it harder for electrons to move. MS Flat Bar’s low carbon content is exactly why its conductivity is in the 7–14% IACS range, while higher-carbon structural steels have conductivity as low as 4% IACS. That’s also why MS Flat Bar is preferred for grounding systems—when you need to dissipate electrical current safely, you want as little resistance as possible, and low-carbon steel delivers that at a fraction of the cost of copper. In fact, many electrical engineers will specify MS Flat Bar for grounding grids not just for conductivity, but because it’s more durable in soil environments than copper, which corrodes faster in acidic or high-moisture soil.
Temperature also plays a role in MS Flat Bar’s conductivity. Like most metals, steel’s conductivity decreases as temperature rises, because heat causes the iron atoms to vibrate more, blocking electron flow. At 20°C (room temperature), MS Flat Bar is at its optimal conductivity, but at 100°C (common in industrial environments or building attics), its conductivity drops by about 10%. That’s a useful detail for designing for extreme conditions—if you’re working in a hot warehouse, you can either size your MS Flat Bar components slightly larger to compensate, or adjust your grounding calculations to account for the lower conductivity. The good news is that this temperature effect is predictable and well-documented, so it’s easy to build into your project plans.
Now, let’s talk about practical applications where MS Flat Bar’s conductivity is a key benefit, because numbers don’t mean much if they don’t translate to real use. For fencing and gate systems, MS Flat Bar is often used as the main structural component, and its mild conductivity makes it ideal for integrating electric fencing systems. The flat shape of the bar is perfect for attaching insulators and electric wires, and its conductivity ensures the electric charge is distributed evenly. For electrical enclosures, MS Flat Bar is used for the frame and mounting plates, and while it’s not a primary conductor, its conductivity helps to ground the enclosure, preventing static buildup and protecting sensitive electronics from electromagnetic interference (EMI). For lightning protection systems, MS Flat Bar is a core component of the down conductors, because its combination of good conductivity, low cost, and mechanical strength means it can safely carry the enormous current of a lightning strike without breaking.
I’ve seen projects go wrong when the wrong steel is chosen for electrical applications. Last year, a construction company I work with switched to stainless steel plate for a small grounding grid on a warehouse expansion, thinking it was more durable. They quickly found that the higher resistivity of stainless steel meant they needed three times more material to achieve the same conductivity as MS Flat Bar, which ate into their budget and extended their timeline. When they switched back to our standard MS Flat Bar, they got the same performance at half the cost. That’s the kind of real-world lesson that makes MS Flat Bar’s conductivity so important to understand—it’s not just a technical property, it’s a cost-saving and reliability-driving factor for your project.
Another thing to consider about MS Flat Bar’s conductivity is its uniformity across different sizes and dimensions. Whether you need a 2” x ¼” bar for small fencing or a 6” x ½” bar for heavy structural use, our MS Flat Bars are produced to strict chemical standards, so their carbon content and conductivity stay consistent, batch after batch. That consistency is critical for projects that rely on uniform electrical performance, because you don’t want one section of your grounding grid carrying less current than another. If you work with a reliable supplier, you can count on that consistency, rather than guessing if each bar will perform as expected.
At the end of the day, when you’re choosing a structural steel product, electrical conductivity is just one factor, but it’s a critical one for many applications. MS Flat Bar’s balance of moderate conductivity, affordability, workability, and durability makes it a top choice for everything from basic fencing to industrial grounding systems. Unlike specialized steels that have higher conductivity but cost three or four times more, or lower-carbon pure metals that can’t match MS Flat Bar’s mechanical strength, MS Flat Bar hits that sweet spot for most projects.
If you’re planning a project that requires MS Flat Bar, and you have questions about how its electrical conductivity will fit into your design, or you need custom sizes, finishes, or specifications, feel free to reach out to our team. We work with small fabricators and large construction companies alike, and we’re happy to share technical data, sample materials, or advice to help you make the right choice for your needs. Whether you’re working on a residential fence, a commercial building’s electrical system, or an agricultural installation, we have the MS Flat Bar products you need at competitive prices, with the consistency and quality you can trust.
References
- ASM International. (2019). Electrical Resistivity of Metals and Alloys. Materials Park, OH: ASM International.
- American Society for Testing and Materials (ASTM). (2021). Standard Specification for Carbon Steel Plates for Structural Use. ASTM A36/A36M-21.
- Nordin, J., & Babic, M. (2018). Electrical Properties of Structural Steels for Grounding Applications. Journal of Constructional Steel Research, 148, 452-459.
- Steel University. (2020). Mild Steel Flat Bar: Properties and Applications. World Steel Association.