One of the questions we get asked most often is how do NEMA and IP ratings compare. That is, can one find an enclosure with a NEMA rating and use it to fit a required IP rating? The quick answer is no as there are different types of tests and even different testing bodies who set these ratings. However, if your purpose is to just determine which NEMA is closest to a specific IP rating and vice versa, there are similarities. First, some definitions. Electrical enclosures are rated based on their ability to withstand a varying degree of environmental elements, including dust, water, and ice. In the United States, the National Electrical Manufacturers Association developed the NEMA rating for classifying an enclosure’s level of protection from those environmental elements. The International Electrotechnical Commission (IEC) http://www.iec.ch/index.htm has developed an alternative rating system, the IP standard, which stands for Ingress Protection. The standard format is “IP’ followed by two numbers which designate the level of protection. The first digit, which ranges from 1-6, specifies the level of protection from solids, and the second digit, which ranges from 1-8, specifies the level of protection from water. The higher the number is, the greater the level of protection. For instance, an enclosure with a rating of IP10 would offer less protection than an enclosure that is rated at IP54.
The following table summarizes the various IP number designations:
|First Number|| Protection|
|Second Number||Protection From Water|
|0||No protection||0||No protection|
|1||Protected from solid objects \|
|1||Protected from vertically falling drops of water|
|2||Protected from solid objects |
|2||Protected from direct sprays of water up to 15 degrees from vertical|
|3||Protected from solid objects over 2.5mm||3||Protected from direct sprays of water up to 60 degrees from vertical|
|4||Protected from solid objects over 1mm||4||Protected against sprays from all directions – limited ingress permitted|
|5|| Protected from dust-limited |
|5||Protected from low pressure jets of water from all directions – limited ingress permitted|
|6|| Totally |
protected from dust
|6|| Protected against strong jets of water – limited ingress |
|NA||7|| Protected from the effects of |
temporary immersion between 15cm and 1m
|NA||8||Protected against long periods of immersion under pressure|
There is not a direct correlation between NEMA ratings and IP ratings, as the two systems are based on a different set of variables. However, the table below shows an approximate cross reference that can be used to help determine the IP number that meets or exceeds a particular NEMA rating.
|4 and 4x||55|
|6 and 6p||67|
|12 and 12k||52|
As always, if you have any questions, don’t hesitate to contact us for more information.