Quick Guide to Common NEMA Ratings

The National Electrical Manufacturer's Association created NEMA ratings in order to provide a common set of standards for NEMA enclosure design and selection. NEMA ratings define the level of protection that an enclosure will provide.

In an industry survey, more than 70% of engineers were confused by the different NEMA ratings. Experts at Bud estimate that 40% of all enclosures that require protection are specified to the wrong level, either inadequate protection, or overkill protection that increases cost unnecessarily.

NEMA 1: The enclosure protects against falling dirt and incidental contact with the internal equipment. This is a basic level of protection: mostly it prevents fingers from entering the enclosure.

NEMA 12: Often the most misunderstood of the ratings. It provides protection against falling dirt, circulating dust, and dripping and lightly splashing liquids. For indoor use only.

NEMA 4: Provides greater protection than NEMA 12. Protects against rain, sleet, snow, wind-blown dust and hose-directed water. Can withstand the formation of ice. Can be used indoors or outdoors.

NEMA 4X: The same protection as NEMA 4 but provides an additional level of protection against corrosion.