Wind, rain, heat, water, corrosion—these are the environmental hazards that electronics enclosures are designed to protect against. The NEMA enclosure rating system is an important tool that electronics manufacturers use to determine the level of protection that their applications demand and find enclosures that suit their needs. Corrosion, however, is a special case that requires enclosure manufacturers to take some extra steps to ensure their products are resistant.

That’s why the NEMA 4X standard exists. NEMA 4X provides all of the protection of a NEMA 4 enclosure, but with added resistance to corrosion. In this article, we’ll talk about why this standard is so useful for equipment manufacturers, and we’ll give you a glimpse into the secrets of how Polycase creates state-of-the-art corrosion-resistant enclosures.

What Is Corrosion—and How Can You Resist It?

To look at how a structure (such as an electronics enclosure) resists corrosion, we first need to understand why corrosion happens. Corrosion is the process that occurs when a metal is exposed to the elements and begins to decay into a form that’s more chemically inert and less reactive.

Rusting is the best-known and most obvious example of corrosion. When a metal that rusts easily, such as iron or mild steel, is exposed repeatedly to oxidizers such as salt water, it begins to transform into substances such as iron oxide—better known as rust. And while rust might be more chemically stable, it’s obviously not a durable or desirable enclosure material.

Polycase’s NEMA 4X enclosures are made of corrosion-resistant materials such as stainless steel, anodized aluminum and polycarbonate. These materials achieve their corrosion resistance through several key properties:

• Metals such as steel need other metals added during their creation to increase their resistance to corrosion. In the case of stainless steel, this means adding metals such as nickel and chromium. These metals don’t behave like crumbly, useless iron oxide when they corrode. They actually form layers inside the steel that strengthen it and prevent it from deteriorating.
• Some metals, such as aluminum, are naturally more resistant to corrosion. This property can be further developed by processes such as anodization, which forms a layer of highly corrosion-resistant aluminum oxide on the surface of the material.
• Non-metallic materials, such as polycarbonate, are naturally resistant to many forms of corrosion thanks to their stable molecular structure. Processes that corrode metal, such as saltwater oxidation, simply do not affect many of these materials.

Which Applications Need a NEMA 4X Enclosure?

Protection against corrosion is vitally important for many work environments. Some of the most common applications of NEMA 4X enclosures include:

• Marine Environments: Salt and brackish water is a major corrosion hazard to electronic enclosures and devices. Any device that frequently encounters salt water, particularly in offshore applications such as oil and gas drilling rigs, will need at least a NEMA 4X enclosure.
• Freshwater Environments: Although fresh water doesn’t have the corrosive power that salt water does, it still presents a considerable corrosion hazard, particularly if it contains chemicals that facilitate corrosion or if the enclosure gets wet frequently.
• Chemical Environments: Corrosive chemicals are an essential component of many manufacturing processes. Devices that may come into contact with these chemicals should have a NEMA 4X enclosure to protect them (although it’s also important to ensure that the material you choose is resistant to the particular chemicals of concern, as not all materials and chemicals behave the same.)

What NEMA 4X Enclosure Options Does Polycase Have?

Polycase is proud to offer our customers enclosure solutions with a variety of NEMA ratings, and NEMA 4X is one of our most popular. Our NEMA 4X options include:

• SA Series: Our stainless steel SA Series offers high-grade NEMA 4X protection. These models also feature a keyed latch for extra security, as well as external mounting brackets and bonding studs for a complete enclosure solution that’s extremely durable, waterproof, and corrosion-resistant.
• ML Series: The ML Series, crafted from heavy-duty polycarbonate, is another great option for corrosion resistance and rugged outdoor performance. It’s NEMA 4X-rated and UL94-V0 flame rated. The polycarbonate construction also offers superior UV protection, and the silicone rubber gasket ensures durable resistance to the adverse conditions.
• AN Series: If your application demands true watertight outdoor-ready performance as well as elegant looks, the AN Series is an excellent choice. These die-cast aluminum enclosures are rated all the way up to NEMA 6P for resistance to prolonged submersion. That also includes NEMA 4X-grade corrosion protection thanks to the AN Series’ aluminum construction. The AN Series is available in either a natural or a black powder-coated finish for true aesthetic excellence.

Polycase SA-33 stainless steel enclosure

Manufacturers or anyone else who needs a corrosion-resistant enclosure will love the durable, rugged performance of Polycase’s NEMA 4X-rated enclosures. If you’ve got more questions about how our enclosures can protect your equipment from corrosion and other environmental hazards, we’re here to help! Call us at 1-800-248-1233 or contact us online to get in touch with our enclosure experts.