NEMA 4X vs NEMA 12 – Overview, Applications, Differences

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NEMA 4X and NEMA 12 characterize degrees of protection in line with specifications from the National Electrical Manufacturers Association. In this article, you will learn about the NEMA vs IEC standards, the characteristics of the NEMA 4X and NEMA 12 ratings, and also compare both ratings.

NEMA enclosure (Such as NEMA 4X and NEMA 12)
Courtesy: Polycase

NEMA VS IEC Standard

Electronic and electrical products have become a fundamental part of human life. As a result, electrical enclosures, which serve to protect users and shield sensitive devices, are common components in or around buildings. Moreover, there are different types of enclosures that have ratings depending on the level of protection. When it comes to industrial applications, two organizations are popular for setting standards for these ratings. These organizations are the International Electrotechnical Commission (IEC) and the National Electrical Manufacturers Association (NEMA).

RegionUnited StatesInternational
Standard for EnclosuresNEMA 250IEC 60529
Rating ScaleNEMA ratingIngress Protection (IP) rating
Factors Affecting RatingConsiders a wider variety of factors ranging from basic protection against solid intrusion, to full submersion, to containing internal explosions.Range of consideration limited to degree of protection against solid ingress, particulate solid admittance, and water ingress.
Components CoveredCovers protection of both internal and external components.Only considers protection of internal components.

When comparing both standards, NEMA considers more factors in developing closure ratings. Thus, NEMA ratings include over 20 different varieties. Two of the most commonly specified industrial enclosures are the NEMA 4x and NEMA 12.

Characteristics of NEMA 4x

NEMA 4X enclosures register among the most common out of the 20 different ratings due to its versatility. The design of this rating ensures the protection of electrical equipment from damaging environmental conditions including rain, dirt, and ice formation. Also, the ‘X’ in its name is indicative of its protection against corrosion. Thus, NEMA 4X offers an adaptable design with several protective qualities including:

  • A robust design that suits both indoor and outdoor locations.
  • Gasketed protection to prevent liquid and solid ingress. The liquid ingress protection protects against rain, sleet, and snow. The solid ingress protection prevents airborne dust, dirt, fibers, and other foreign objects from gaining access into the enclosure.
  • In addition, the materials for constructing this enclosure are corrosion resistant or those that passivate quickly. Examples include polycarbonate, aluminum, and stainless steel.
  • Protection of external components from damage due to ice formation.


Due to its adaptability, NEMA 4X rating serves in a variety of industry applications.

  • Manufacturing Facilities: When indoors, NEMA 4X can serve in facilities where there is significant amount of dust or other airborne contaminants. Also, it is suitable for facilities that have corrosive substances such as water treatment plants and marine environments.
  • Outdoor Facilities: On the other hand, as outdoor equipment, it serves in car washes, high-pressure cleaning equipment areas, and other areas with frequent washdowns with water or chemicals.

Characteristics of NEMA 12

Generally, NEMA 12 enclosures are ideal for moderate indoor protection against liquid and solid ingress. Because the level of protection is basic, it is suitable for domestic use and more affordable than many counterparts. Furthermore, some of its features are:

  • Solid ingress protection such as falling dirt, circulating dust, and fiber.
  • Generally, it offers water ingress protection against dripping or minor splashing. Also it protects against dripping and light splashing of non-corrosive liquids, including seepage of oil and coolants from external sources.
  • NEMA 12 also protects against accidental personnel contact.


Although NEMA 12 enclosures serve only indoor use, it is common in a variety of applications. Some of these include:

Differences Between NEMA 4X vs NEMA 12

Comparing the features of NEMA 4X and NEMA 12 is straightforward because they are from the same standard. In fact, choosing between these two enclosures is a fairly common endeavor.

Adaptable to both indoor and outdoor applications.Restricted to only indoor applications.
Provides protection against windblown dust and rain.Its level of protection is limited to dust and other particles in circulation by air. Then, light splashing or dripping of liquids.
These enclosures are corrosion-resistant.Offers no protection against corrosion.
Protects external components from the effect of ice formation.No protection from the effects of ice formation on the enclosure.
NEMA 4X vs NEMA 12

Engineers generally tend to choose NEMA 12 if it can meet environmental requirements due to its lower costs.