NEMA Ratings
NEMA (National Electrical Manufacturer's Association) has a standard, NEMA 250-1997, to designate the degree of protected provided by electrical enclosures.
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NEMA 1 |
NEMA 3R |
NEMA 4 |
NEMA 4X |
NEMA 5 |
NEMA 6 |
NEMA 6P |
NEMA 12 |
NEMA 13 |
Indoor use only |
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Indoor and outdoor use |
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Falling liquids and light spasling |
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Non-hazardous dust, lint, & fibers |
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Washdowns and splashing water |
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Oil and coolant seepage |
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Oil and coolant spraying and splashing |
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Corrosive agents |
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Occasional temporary submersion |
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Occasional prolonged submersion |
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NEMA 7 and NEMA 9 enclosures are rated for hazardous locations; both are for indoor use. NEMA 7 enclosures meet Class I, Group A, B, C, and D. They're designated to contain an internal explosion without causing an external hazard. NEMA 9 enclosures meet Class II, Division 1, Group E, F, and G. They're designed to prevent the ignition of combustible dust. |
IP Ratings
The IEC (International Electrotechnical Commission) developed their own IP (Ingress Protection) Standards, IEC 60529, for the degree of protection provided by enclosures. IEC designations consist of the letters "IP" followed by a two-digit number:
First Digit - Protection with respect to ingress of solid foregin objects.
1 - Protection from solid objects greater than 50 mm in diameter
2 - Protection from solid objects greater than 12.5 mm in diameter
4 - Protection from solid objects greater than 1 mm in diameter
5 - Protection from dust that would interfere with equipment operation
6 - Dust tight
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Second Digit - Protection with respect to harmful ingress of water.
0 - No protection
2 - Protection from vertically dripping water
4 - Protection from splashed water
5 - Protection from water projected from a nozzle
6 - Protection from heavy seas or power jets of water
7 - Protection from temporary submersion
8 - Protection from continuous submersion |
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