Understanding UL Certification in Powder Coating

By Danielle Dykstra

As industries continue to innovate in product design, especially in critical sectors like electrical infrastructure and enclosures, the importance of compliance and durability grows. One certification that frequently surfaces in these conversations is the UL 1332 standard. This is a recognition that plays a key role in qualifying powder coatings for use on outdoor electrical equipment.

What exactly does Underwriters Laboratories (UL) recognition mean in the world of powder coating, and how does a product or coating system earn it?

What Is UL 1332?
UL 1332 is a standard developed by UL that specifies requirements for opaque and clear organic coatings used on steel enclosures of outdoor use electrical equipment. These coatings serve as a barrier, protecting the metal from corrosion and ensuring long term product durability.

The scope of UL 1332 includes:

• Coatings applied to both exterior and interior surfaces.
• Systems that may include one or more coats.
• Specific application methods and pretreatments.
• Required curing processes and film thicknesses.

It’s important to note that UL 1332 recognition applies to the coating as a component. Final approval still depends on its integration into a complete UL-certified product.

What’s Required for UL Recognition?
For a powder coating to be recognized under the UL 1332 standard, it must meet several strict criteria related to application, performance, and consistency. Diamond Vogel, for example, has earned UL 1332 recognition (File MH29927) for a TGIC polyester powder coating platform and an epoxy primer.

Here's what that process involves:

• Substrate preparation: Multistage pretreatments applied to hot-rolled steel or cold-rolled steel.
• Application method: Electrostatic spray.ure schedule: 10–30 minutes at a peak metal temperature (PMT) of 320–390° Fahrenheit.
• Minimum film thickness: At least 2.0 mils of dry film thickness.
• Resin types: Recognized systems include TGIC polyester and epoxy primers.
• Color options: Any solid color with a 60-degree gloss between 30 and 100, including sandy or grainy textures.

In practice, this means manufacturers must work within very specific boundaries. Deviating from an approved cure schedule or applying a thinner film than specified could invalidate the UL recognition and compromise compliance.

The Process of Achieving UL Certification
Recognition starts with coating performance but ends with the complete system. Manufacturers submit their powder coating formulas to UL for evaluation, which includes testing under standardized conditions. Once approved, the coatings are authorized to display the UL Recognized Component Mark.

Testing typically involves a range of environmental and mechanical test protocols, including salt spray resistance, impact resistance, and adhesion strength. UL also evaluates the consistency of application and curing, ensuring repeatability under real-world production conditions.

But this doesn’t mean automatic UL approval for any product using that coating. The final assembled product still must undergo its own UL evaluation, and UL will review how all components, including the coating, work together to meet the required safety and performance standards.

That said, using a UL Recognized coating system can significantly streamline the certification process for original equipment manufacturers, especially when paired with strong documentation and consistent application practices. It provides confidence that the coating will meet the performance expectations required for full product certification.

Applicators: Do They Need UL Certification Too?
Unlike other standards such as AAMA for architectural coatings, UL 1332 does not require the applicator to be individually certified. However, they do need to follow the specific Conditions of Acceptability outlined in the recognition:

• Approved substrates and pretreatments.
• Correct electrostatic spray method.
• Precise cure schedules and film builds.

If these guidelines are not followed, the coating may fall out of compliance, even if the product itself is UL Recognized. For this reason, applicators play a vital role in maintaining the integrity of a UL Recognized system.

Applicators should work closely with powder manufacturers to maintain process control, record application conditions, and train personnel on recognition requirements. Quality assurance measures such as batch tracking, oven profiling, and substrate cleanliness checks are important to ensure compliance.

Where Is UL Recognition Most Important?
UL 1332 coatings are widely used in industries that manufacture electrical enclosures, junction boxes, power distribution systems, and control panels. These components form the backbone of industrial, commercial, and utility-scale electrical infrastructure. In these environments, coatings serve as the line of defense against corrosion, moisture, UV exposure, and chemical contaminants.

Electrical boxes and power distribution panels, in particular, benefit from UL Recognized coatings due to their constant exposure to environmental hazards, especially in outdoor or semi-enclosed settings such as substations and transportation hubs. These units must maintain functionality over years of service, and even minor surface failures can escalate to compromised insulation, short circuits, or system downtime.

UL Recognized powder coatings ensure that these enclosures can endure the physical and thermal stresses encountered in their operating environments. In addition, manufacturers building UL-listed electrical products often select only UL Recognized coatings to reduce approval timeframes and demonstrate compliance throughout their product lines.

With the rapid growth of the EV market and the expansion of renewable energy systems, the need for certified, durable coatings is increasing. From high-voltage power management cabinets to low-voltage terminal housings, UL recognition provides confidence to manufacturers and contractors.

Other growing applications include smart grid infrastructure, battery storage systems, and backup power solutions. These are examples where coating reliability directly impacts product lifespan and safety.

The Broader Impacts of UL Certification
As regulatory requirements continue to evolve, especially for products used in electrical systems and outdoor environments, UL certification is increasingly seen not only as a compliance tool but also as a competitive differentiator. More procurement departments, engineers, and specifiers now require UL Recognized components as part of their internal quality standards, particularly when bidding on infrastructure or government projects.

UL recognition also supports risk management by reducing the likelihood of failure in high-stakes environments. A failure of a powder coated electrical enclosure in an exposed environment can have cascading consequences, from operational downtime to safety hazards or warranty claims. By choosing UL Recognized coatings, manufacturers proactively demonstrate their commitment to product integrity and customer protection.

Another benefit lies in global supply chain validation. For international manufacturers sourcing components from different regions, UL recognition provides a trusted baseline that helps unify expectations. It acts as a common language between OEMs, suppliers, and regulators across borders, especially in markets where domestic certification infrastructure may not be as robust.

From a materials science perspective, the performance thresholds required for UL 1332 recognition push formulators to refine their systems for enhanced corrosion resistance and coverage. In other words, the use of UL recognition typically increases all product quality.

As sustainability continues to shape the coating industry, UL Recognized powder coatings align well with environmental goals. They are solvent-free, generate minimal VOCs, and reduce waste through precise electrostatic application. For environmentally conscious manufacturers, UL recognition paired with powder technology offers a responsible path to regulatory alignment and long-term product success.

The Value of UL Certification
For manufacturers, UL recognition is more than just a label, it’s a commitment to safety, performance, and reliability. A UL Recognized powder coating:

• Enhances product credibility.
• Assists with compliance during product certification.
• Simplifies the approval process with UL.
• Adds a layer of assurance for end users and regulators.

UL recognition offers a major advantage by boosting confidence throughout the supply chain. For manufacturers and designers, UL Recognized coatings simplify design approval and help meet strict purchasing standards. From a marketing standpoint, having UL recognition shows a company’s dedication to quality, making products more appealing to buyers who rely on verified performance standards. Engineers, contractors, and procurement teams often prefer materials with the UL Recognized mark because it helps them manage risk and stay compliant with regulations.

As the industry continues to advance, UL certification remains a powerful tool for manufacturers who want to lead with both compliance and accountability.

Danielle Dykstra is business development and technical services manager for Diamond Vogel, Inc.