Do photovoltaic bolts need corrosion protection?

In solar power systems, every component—from the panels to the mounting structure—plays a vital role in ensuring performance and longevity. However, one often-overlooked element is the bolt. Photovoltaic (PV) bolts may appear small and simple, but they are critical to the structural stability and safety of solar installations. One of the most important factors affecting their performance is corrosion protection. So, do photovoltaic bolts need corrosion protection? The answer is a definite yes—and here’s why.

1. The Harsh Outdoor Environment

Photovoltaic systems are almost always installed outdoors—on rooftops, open fields, deserts, or coastal areas—where they are constantly exposed to sunlight, rain, humidity, wind, and dust. In such conditions, metal components are vulnerable to oxidation and corrosion. Over time, moisture and oxygen react with the metal surface, leading to rust formation.

If PV bolts corrode, the structural integrity of the solar array can be compromised. Rusted bolts lose strength, loosen easily, and may eventually break, which can cause panels to shift, vibrate, or even detach. This not only affects system efficiency but also creates serious safety hazards.

Therefore, corrosion protection is not an option—it’s a necessity for any solar installation designed to last 20–30 years.

2. Materials Used for Anti-Corrosion Performance

To resist corrosion, photovoltaic bolts are usually made from or coated with anti-corrosive materials. The most common options include:

• Stainless Steel (304/316) – These alloys contain chromium and nickel, which form a passive oxide layer on the surface that resists rust and pitting. Type 316 stainless steel is especially resistant to salt and humidity, making it ideal for coastal or humid environments.
• Hot-Dip Galvanized Steel – A thick layer of zinc is applied to carbon steel bolts through a hot-dip process. Zinc acts as a sacrificial coating, corroding first to protect the steel underneath. This method provides durable and economical protection for large-scale installations.
• Zinc-Nickel Alloy Plating – This modern coating combines the corrosion resistance of nickel with the sacrificial properties of zinc. It’s widely used in high-performance PV mounting systems where longevity is essential.
• Dacromet or Geomet Coatings – These are non-electrolytic coatings that offer excellent corrosion resistance without hydrogen embrittlement. They are often used when both environmental compliance and long-term durability are required.

Each material choice depends on the installation environment, budget, and expected lifespan of the solar project.

3. How Corrosion Affects System Performance

Corrosion doesn’t just make bolts look old or dirty—it has real mechanical and electrical consequences. As corrosion progresses:

• Tensile strength decreases, reducing the load-bearing capacity of the structure.
• Bolts loosen, causing misalignment or vibration of solar modules.
• Electrical grounding may be compromised if the bolts are part of the grounding system.
• Maintenance costs increase, since replacing corroded bolts on a large solar farm can be labor-intensive and expensive.

Without corrosion protection, a solar system’s reliability and efficiency can decline significantly within just a few years—long before the panels themselves reach the end of their lifespan.

4. Environmental and Regional Factors

The need for corrosion protection also depends on where the PV system is installed:

• In coastal areas, salt spray accelerates corrosion dramatically, so marine-grade stainless steel is essential.
• In humid or tropical climates, condensation and rainfall promote rust formation.
• In desert environments, temperature fluctuations and sand abrasion can damage coatings, exposing metal surfaces.
• Even in urban areas, pollution and acid rain can cause chemical corrosion over time.

For these reasons, choosing the correct anti-corrosion solution is a key step during system design and material selection.

5. Maintenance and Longevity

Even with corrosion protection, regular inspection is important. Installers and maintenance teams should check bolts periodically for rust, discoloration, or loose connections. Early detection allows for timely replacement before structural or electrical issues arise. Using torque-controlled tightening and proper washers can also prevent water penetration and reduce corrosion risk.

In well-designed systems, corrosion-protected bolts can last as long as the solar panels themselves—typically 25 to 30 years—ensuring system safety and minimizing maintenance costs.

6. The Bottom Line

Corrosion protection is not just about aesthetics—it’s about safety, reliability, and efficiency. Photovoltaic bolts are small but crucial components that hold entire solar structures together. Without proper protection, even the best panels and frames can fail prematurely.

Choosing the right material—whether stainless steel, galvanized steel, or advanced coated bolts—is a smart investment in the system’s future. It ensures that solar installations can withstand years of weather exposure while maintaining stability and performance.

Conclusion

Yes, photovoltaic bolts absolutely need corrosion protection. They operate in demanding environments and must maintain their strength and integrity for decades. Through the use of high-quality materials, protective coatings, and regular maintenance, solar systems can achieve their full lifespan safely and efficiently.

In short, protecting the smallest components—like bolts—helps protect the entire photovoltaic system and ensures that clean energy continues to flow for years to come.