Electrical Enclosures are rated on how resistant they are to the ingress of particles and water. There are two standards which indicate the enclosures protection level these are: NEMA ratings and IP ratings. Each of these define how much protection an electrical enclosure offers against the ingress of water and dust. However, each uses a different test methods and parameters to qualify the enclosure. The standards for testing these are as follows:

NEMA Rated Enclosures: NEMA 250

IP Rated Enclosures: IEC Standard 60529

What is NEMA?

The acronym NEMA stands for National Electrical Manufacturers Association (NEMA). NEMA is an association of electrical equipment manufacturers throughout the United States. NEMA ratings are generally only associated with electrical enclosures sold within the USA and IP ratings used elsewhere. However, occasionally NEMA is referenced in different regions throughout the world.

NEMA has over 600 published standards for Enclosures and Connections and are responsible for the standardization of protection throughout the US. The most common NEMA Enclosure Standards are below:

  • NEMA 4X – Protection against ingress of dust and hoesdown or splashing water
  • NEMA 6P- Protection against ingress of dust and ingress of water (prolonged submersion)

What is IP?

IP Ratings are in international standard which is not controlled by any one government and are part of the International Electrotechnical Commission (IEC).

“IP” stands for International Protection however, it is more commonly referred to as Ingress Protection. This is especially true with Electrical Enclosure Manufacturers. Some of the most common IP standards are as below:

  • IP65 – Dust Tight and protection against water sprayed from a nozzle
  • IP67 – Dust Tight and protection against immersion between 15cm and 1 meter
  • IP68 – Dust Tight and Water Tight: Protected against immersion

What is the difference between NEMA and IP?

NEMA is predominately used only within the USA for industrial applications whereas IP ratings are used universally worldwide.

IP ratings only cover the protection against ingress of water and particles, whereas NEMA ratings do the same but, also include a protection standard for corrosion resistance and gasses. NEMA uses the additional protection rating to assist with Enclosure selection within harsh, corrosive, or hazardous environments.

Are NEMA and IP the same?

Whilst there is no direct conversion between NEMA and IP ratings they can be similar, and comparisons can be drawn. However, the two rating systems cannot be directly converted between one and the other.

The NEMA rating system incorporates an extra feature for corrosion protection which the IP rating system does not. Its is important to keep this in mind if your electrical enclosure will be located in a harsh or hazardous environment.

Some common comparisons between IP and NEMA are shown below:

  • IP66 / IP67 – are commonly compared with NEMA 4X
  • IP68 – is commonly compared with NEMA 6P

Review

The IP and NEMA Ratings are two different standards and not directly comparable. Whilst both Standards outline the protection an enclosure offers against water and dust ingress, only the NEMA Standard has protection levels for corrosion resistance. NEMA is generally the accepted Standard in the USA and Nth America, whereas the IP rating system is utilized elsewhere throughout the world.