Choosing the right enclosure rating protects equipment and avoids paying for protection you do not need. Two systems appear in specifications: NEMA types, common on North American projects, and IP codes, the usual choice in India.
NEMA 250 types
NEMA 250 defines enclosure types by the environment they are built for. Common examples:
- Type 1: indoor use, protection against contact and falling dirt
- Type 3R: outdoor use, protection against rain, sleet and snow
- Type 4: indoor or outdoor, protection against hose-directed water
- Type 4X: as Type 4, plus corrosion resistance, often in stainless steel
- Type 12: indoor industrial use, protection against dust, dripping and light splashing
IP codes
IEC 60529 IP codes use two digits: the first rates protection against solid objects and dust (0 to 6), the second against water (0 to 9). IP54, for example, is dust protected and splash proof; IP66 is dust tight and protected against powerful water jets.
How they compare
A NEMA type meets or exceeds a particular IP code for solids and water, but NEMA types also cover conditions such as corrosion, icing and oil. So a NEMA type can be converted to a minimum IP code, but an IP code cannot be converted to a NEMA type.
Indian requirements
In India, degree of protection is specified as an IP code to IS/IEC 60529, the Indian adoption of IEC 60529, and low-voltage switchgear assemblies follow the IS/IEC 61439 series.
See our sheet metal cabinets and enclosures page.