Nearly all premature failures in control panels are the result of under specification in at least one of four areas: hinge, latch, gasket and climate control. Each requires unique considerations and design elements to support their success. Control enclosures are tasked with protecting sensitive controls in a variety of harsh environments. If these varying environmental conditions are not considered in system designs, it can lead to damage and costly downtime. To specify an enclosure designed with features suitable for harsh environments, there must be consideration for the four aspects of design that are commonly overlooked. This attention to detail up front improves successful longevity in design.
Hinge
The hinge provides a secure seal and adds security to the enclosure. Stainless steel material with lift-off capability for enclosure door hinges are the best choice for harsh environments to prevent premature failure.
Additionally, lift-off hinges allow for easy access to the interior of the enclosure, making it simpler to perform modifications, integration, maintenance and inspections. The highest performing hinges are robust, removable and made of a durable material.
Latch
When selecting a latch to endure a harsh environment, material matters. Standard industrial enclosure latching made with zinc-plated material is low cost but generally not suitable for harsh environments. Stainless steel is the ideal solution for the full latch assembly.
A properly designed latch makes it easier to access and secure the enclosure, providing long-term success. When a tool is required to latch and fully secure the enclosure, it can be easily overlooked in the field which leaves the controls prone to the environmental effects and ingress of fluids like rain in outdoor applications.
Gasket
While choosing the optimal enclosure construction and design for harsh environments is essential, selecting a highly reliable seal or gasket is a critical component for the enclosure’s success. Gaskets are the most common failure point for a control enclosure. Gaskets and their adhesives must be constructed of materials that are compatible with the environment they are installed in. High humidity, large temperature swings and ambient chemicals can quickly degrade some of the most common gasket materials like polyurethane foam. Selecting either an improved material like silicone or an adhesive-free, compression held silicone gasket is a best practice for the more difficult applications like wastewater treatment and oil and gas. The gasket is the most critical point of design since it protects the enclosure from external environmental fluids, humidity and moisture.
Climate Control
Harsh environment considerations must be prioritized to protect the metals associated with common cooling systems. These may include copper tubing and any traditional evaporative and condensing coils for cooling the internal environment of the enclosure. These coils, copper and braze materials can be easily protected with specific coatings designed for these harsh environments such as extreme environment air conditioners or other climate control systems that offer advanced corrosion protection packages. Enclosures can overheat due to external factors such as direct sunlight, warm processing equipment or internal factors like the heat load of components inside the enclosure. Heat can damage and significantly reduce the life of electrical equipment. The life expectancy of electronics is cut in half for every 18 degrees F they operate above room temperature.
Understanding Ratings
When determining design elements for control enclosures, it is important to pay attention to ratings and their qualifications. The National Electrical Manufacturers Association (NEMA), Underwriters Laboratories Inc. (UL) and Canadian Standards Association (CSA) are standard writing organizations commonly recognized in North America. Their ratings are based on similar application descriptions and expected performance. UL and CSA require enclosure testing by qualified evaluators. UL also sends site inspectors to both manufacturers and integrators to ensure that they adhere to prescribed methods and material specifications. NEMA does not require Nationally Recognized Testing Laboratory (NRTL) testing and leaves compliance entirely up to the manufacturer. IP ratings unless paired with a certificate from an NRTL are also self-declared without audit or procedure compliance accountability. It’s also important to note that an integrated enclosure rating can only be as high as the lowest rating of the components that penetrate the surface of the enclosure such as an HMI screen or pushbutton. This makes it critical to ensure both the enclosure and components are properly rated for harsh environments.
nVent provides a uniquely comprehensive enclosure portfolio to protect critical electrical equipment for all environments. These solutions are specially engineered to meet the simplest to most challenging application needs.
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