Meeting NEMA Ratings for Electrical Enclosures: A Low Cost, Low-Risk Solution
Mallory McGuinness | March 18, 2021
While electrical enclosures are typically chosen to protect building, industrial, and utility application electronics from liquid exposure, this method can be overly complicated and expensive due to the need for customization to meet stringent protection requirements. Although bulky, elaborate enclosures may seem like a necessary evil, proven thin-film conformal coatings can be a time and money-saving alternative to consider.
What are NEMA Ratings?
To assure customers that your products can operate reliably and meet industry requirements, design teams often must meet NEMA ratings. The National Electrical Manufacturer Association defines the NEMA rating system and defines a fixed enclosure’s requirements to withstand certain environmental conditions. These standards have rigorous testing requirements to verify protection from corrosive materials, external ice, submersion, dripping and light splashing, oil immersion, and other reliability threats.
The Problem with Enclosures
With enclosures, more reliability can mean more bulk, weight, expense, and complications. As product design teams strive to make enclosure protection failsafe, they are forced to add more seals and gaskets that add unnecessary weight and bulk to devices that may need miniaturization. And usually, the higher the NEMA rating, the higher the cost for design and manufacturing, as teams spend hours ensuring PCBs can become smaller to conform to the size, shape, and space of the enclosure. They must design one for each component, subsequently sending it to the lab for NEMA testing.
There are also hidden costs involved, including extra material resources and labor, which increase the total cost of ownership (TCO) when upgrades or new equipment are added over time. Unfortunately, many design engineers don’t consider these changes until it is too late – after they have to convert to other NEMA ratings, scale-up, or add panels.
Testing for reliability is also expensive and beyond the control of design teams. In each case, a testing engineer must verify the NEMA rating, so they must be knowledgeable and well trained in conducting the test and reporting the results. After the enclosures are designed, the product’s reliability is in their hands, adding an element of risk.
View a webinar about proven corrosion resistant methods delivered by Dr. Sean Clancy, Director of Coating Technology at HZO & Anti-Corrosion Expert
Are Enclosures Reliable?
Although much effort goes into designing to meet NEMA ratings, enclosures may not be that reliable. Moisture can still pass through rubber gaskets and plastic boxes, and sealed boxes do not “breathe.” Trapped moisture has no means of escape and can condense to become sitting water inside the box during colder weather or at night.
Thinking Outside the Box with Protective Thin-film Coatings
Thin-film coatings, protective layers ranging from around 2-50 microns, are increasingly being used to augment enclosure protection. In some instances, they can eliminate the need for sub-enclosures, or they can be used to enhance simplified enclosures in a “belt and suspenders” approach to guaranteed reliability, eliminating excessive cost, bulk, and weight.
Unlike enclosures, thin-film coatings protect from the inside out, with a breathable barrier that can help you meet NEMA ratings. These coatings, including Parylene conformal coating, are polymeric films applied to printed circuit boards, acting as a protective layer.
The chart below details some of the NEMA requirements that you can easily meet with the use of thin-film coatings:
Thin-film capabilities regarding meeting NEMA requirements
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With enclosures, more reliability can mean more bulk, weight, expense, and complications.
It’s easy to meet these relevant requirements because thin-film coatings can be fully submersible and waterproof, depending on coating thickness and usage. And while many chemicals can eat through enclosure materials, including polycarbonate, polyester glass, and stainless steel, thin-film coatings have excellent chemical resistance.
Thin-film coatings are transparent and can deliver at nanometer thinness, reducing bulk and weight. When you work with HZO, you can outsource seamless integration at many points in production or bring the process in-house with help from our experienced technicians.
Ultimately, when it comes to electronic protection, there is no one-size-fits-all process – that’s why we offer multiple solutions that can be tailored to your needs. If you are interested in downgrading your enclosure and meeting NEMA ratings with thin-film coatings, we’re here to help. Reach out to us today for a technical consultation, we would love to speak to you.
Thin-film coatings are transparent and can deliver at nanometer thinness, reducing bulk and weight.
Discover how HZO can protect your product