February 19, 2020
- Url


NEMA ratings are established by the National Electrical Manufacturers Association, a trade group for electrical manufacturers. The NEMA rating system for electrical and electronics enclosures rates an enclosure’s protective qualities along the same lines as the IP system—dust ingress protection and liquid ingress protection—but adds some factors that the IP system doesn’t account for (which we’ll talk about below). Unlike the IP system, NEMA ratings are used primarily within the U.S. Polycase offers our customers great resources for learning about IP ratings and NEMA ratings. Check out our articles–What Are IP Ratings? and The Ultimate Guide to NEMA Ratings–for a deep dive into each topic. Once you understand the rating systems, it’s time to look at how to convert them.
First, find the IP rating you need and then take the first digit and see which NEMA ratings are filled in for column A. Then, do the same with the second digit in column B. A NEMA rating that’s filled in for both columns for your target IP rating will likely provide satisfactory performance.However, remember that NEMA ratings and IP ratings sometimes cannot be lined up perfectly because NEMA ratings include factors that IP ratings do not. Corrosion resistance and operability when covered in ice, for example, are two important factors that only NEMA ratings address. Thus, while a NEMA 4 enclosure can be rated on an IP scale fairly easily, a NEMA 4X enclosure or NEMA 3S enclosure cannot be. Thus, it’s important to use IP ratings only as they were designed: to rate protection against dust ingress and liquid ingress. For enclosures that need to protect against additional factors, know that only an enclosure’s NEMA rating provides the necessary information. On top of that, there’s one more key step to getting a reliable NEMA enclosure or IP enclosure: making sure that its rating has been certified by an independent authority. 
Do you have more questions on converting IP ratings and NEMA ratings, or need some help designing a customized electrical enclosure? Need information on our NEMA rated enclosures and IP rated enclosures? Our enclosure experts would love to hear from you, so just call 1-800-248-1233 or contact us online via email or live chat.