Tips on Selecting a NEMA 4 Enclosure

Tips on Selecting a NEMA 4 Enclosure

Many design engineers are used to specifying NEMA 4 rated enclosures to house their electronics. NEMA 4 enclosures protect their contents from dust, rain, and hose-directed water (think factory washdown). It’s a common rating, and some engineers may specify it reflexively. However, there are considerations to keep in mind before you specify an enclosure at this rating,  

Often, you can avoid specifying mistakes and save money if you know what to look for. Bud offers the following tips on how to cost-effectively select a NEMA 4 enclosure for your application.  

Do you need to protect the entire enclosure, or only a sensitive component?

We see this mistake frequently: engineers specifying a large, costly enclosure instead of protecting just one small part of the design. For example, if only one component needs  NEMA protection, then protect that component with a small die-cast type NEMA box like the one featured in the video below, instead of buying a large NEMA 4 enclosure. 


What level of NEMA protection is required?

The most common mistake is to specify a NEMA 12 enclosure, when in fact NEMA 4 enclosures  offer more environmental protection. On the other hand, don’t over specify, because each increasing level of protection can exponentially increase the cost of an enclosure.  

Consider where the enclosure will be located. Often a NEMA 12 enclosure will work if there is no spray down requirement. Also, there is no point to specifying UV stabilization if a plastic enclosure is being used indoors. A UV rating adds significantly to the cost of a molded plastic enclosure. Review our Quick Guide to Common NEMA Ratings for guidance. 

What material do you need?

Steel is often the choice for a NEMA enclosure, especially for large enclosures where its strength is helpful. However, plastic is less costly and provides adequate protection in many applications. Polycarbonate plastic, ABS plastic, fiberglass (featured in video below), and  die cast-aluminum enclosures  are lower cost materials than steel and should not be overlooked. Fiberglass offers more strength than steel for its weight, and therefore it may be a suitable substitute for large enclosures. 

Can your vendor make modifications?

If you are dealing with more than a few pieces, Bud has the best equipment to easily and affordably modify the enclosure with cutouts and to add cable glands for  NEMA 4X applications. Leave it to the pros; you’ll avoid time-to-market delays and the risk of mistakes. The cost of one mis-cut or broken enclosure may exceed the cost of having the factory make the modifications. 

By the way, because of our 6-axis robotic milling machine and our deep inventory, Bud is able to modify and ship enclosures with unusual speed. In fact, on our common NEMA box enclosures, Bud can make cutouts to your specifications in only five days… the fastest turnaround in the industry.  

On our website, the hundreds of models that qualify for this program are labeled “5 Day Mods.” 

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