Guide to NEMA and IEC Rack Enclosure Ratings

Rack enclosures are rated based on their suitability for certain applications and the degree to which they protect equipment. Each type of enclosure is given a number based on its ability to withstand environmental factors.

There are two main standards: (National Electrical Manufacturers Association) in the U.S., and (International Electrotechnical Commission) worldwide. See the charts below for each standard's rating descriptions.

NEMA logo

NEMA identifies enclosures with a number to represent their specific protection qualities. : NEMA 7, 8, 9 and 10 type enclosures are designated for use in hazardous locations. See the National Electrical Code (NEC) for more information.

Type Protects Against
1Limited amounts of falling dirt
3Rain, sleet, windblown dust, and damage from external ice formation
3RRain, sleet, and damage from external ice formation
3SRain, sleet, windblown dust, and damage from external ice formation; plus provides for operation of external mechanisms when ice laden
4Windblown dust and rain, splashing water, hose-directed water, and damage from external ice formation
4XCorrosion, windblown dust and rain, splashing water, hose-directed water, and damage from external ice formation
6Hose-directed water, entry of water due to occasional temporary submersion (depth limited) and damage from external ice formation
6PHose-directed water, entry of water due to prolonged submersion (depth limited) and damage from external ice formation
7Conditions in locations classified as Class I, Groups A, B, C, or D, as defined in the NEC (National Electrical Code)
8Conditions in locations classified as Class I, Groups A, B, C, or D, as defined in the NEC
9Conditions in locations classified as Class II, Groups E, F, or G, as defined in the NEC
10Mine conditions as defined by the Mine Safety and Health Administration
12Circulating dust, falling dirt, and dripping non-corrosive liquids
12KSame as type 12 but with knockouts
IEC logo

The IEC uses a two digit code to define specific protection capabilities. The first digit describes the degree of protection against access to hazardous parts and ingress of solids and the second digit describes the degree of protection against ingress of water. (e.g. An IP64 enclosure is dust-tight and is protected against splashing water in any direction.)

IEC (First Digit)
Number Protection Against Access to Hazardous Parts(Size of Opening) Protection Against Ingress of Solid Foreign Objects(Size of Opening)
0 Non-protected
1 Back of hand (50mm) ≥ 12.5 mm
2 Jointed finger (12 mm x 8 mm) ≥ 50 mm
3 Tool (2.5 mm) ≥ 12.5 mm
4 Wire (1 mm) ≥ 12.5 mm
5 Wire (1 mm) Dust-protected
6 Wire (1 mm) Dust-tight
IEC (Second Digit)
Number Protection Against Ingress of Water
0Non-protected
1Water dripping vertically
2Water dripping, enclosure tilted up to 15°
3Spraying water, up to 60° angle from vertical
4Splashing water, any direction
5Jetting water, any direction
6Powerful jetting water, any direction
7Temporary immersion in water
8Prolonged immersion in water
Clear List