The Basics of NEMA Ratings

The National Electrical Manufacturers Association (NEMA) is an industrial organization representing electrical equipment and medical imaging manufacturers that sets the standards for the environments in which electrical enclosures can be used. NEMA ratings are derived from these standards. A wide range of industry professionals—including engineers, contractors, and inspectors—use them to understand whether an enclosure is suited for use in a particular environment.

NEMA ratings range from Type 1 (i.e., NEMA 1) Type 13 (i.e., NEMA 13), each of which indicates varying levels of protection against environmental conditions and contaminants. For example, NEMA 4X enclosures are suitable for use in indoor or outdoor environments, where they protect against dust, rain, sleet, snow, water, and ice.

Characteristics of NEMA 4X Enclosures

NEMA 4X enclosures are used in indoor and outdoor non-hazardous locations (i.e., locations without constant exposure to flammable gases). When properly installed, they offer a degree of protection against the following:

  • Ingress of solid foreign objects (i.e., falling dirt, dust, fibers, lint, flyings, etc.)
  • Ingress of water (e.g., rain, sleet, snow, hose water, etc.)
  • Corrosion
  • External ice formation

They are ideal for use in situations where corrosive chemicals are used, such as oil facilities or meat processing facilities. However, they are not suitable for use in environments where they will be subjected to prolonged submersion. For these applications, a NEMA 6P enclosure—which offers the same protections as NEMA 4X with additional resistance to limited-depth submersion—is more appropriate.

NEMA 4 vs. NEMA 4X

NEMA ratings sometimes come with several subsets. For example, there are three NEMA 3 ratings—NEMA 3, NEMA 3RX, and NEMA 3SX. Generally, the variations provide additional protection on top of the existing protection of the base rating.

Between NEMA 4 and NEMA 4X, the main difference is the addition of corrosion resistance. While both ratings indicate some degree of protection against wind, rain, dirt, dust, sleet, snow, hose water, lint, and external ice formation, only NEMA 4X offers protection against corrosion. For this reason, NEMA 4X enclosures are generally fabricated from corrosion-resistant materials such as aluminum or stainless steel.

Contact Selco for Your NEMA 4X Enclosures

NEMA ratings are used by industry professionals across North America to understand which electrical enclosures they need for their applications. For most facilities, NEMA 4X or NEMA 6P enclosures offer the level of protection they need against environmental conditions.

At Selco, we manufacture custom NEMA enclosures, including ones with NEMA 4X and NEMA 6P ratings. Our over 100 years of industry experience and state-of-the-art fabrication facility ensure our enclosures meet high standards for precision, accuracy, and quality. For more information about our custom enclosure solutions, contact us or request a quote today.