Industrial Automation Specialists

NEMA Ratings

NEMA (National Electrical Manufacturer's Association) has a standard, NEMA 250-1997, to designate the degree of protected provided by electrical enclosures.

Environment
NEMA 1
NEMA 3R
NEMA 4
NEMA 4X
NEMA 5
NEMA 6
NEMA 6P
NEMA 12
NEMA 13
Indoor use only
 
 
 
 
Indoor and outdoor use
 
 
 
 
Falling liquids and light spasling
 
 
Non-hazardous dust, lint, & fibers
 
 
Washdowns and splashing water
 
 
 
 
 

Oil and coolant seepage

 
 
 
 
 
 
 
Oil and coolant spraying and splashing
 
 
 
 
 
 
 
 
Corrosive agents
 
 
 
 
 
 
 
Occasional temporary submersion
 
 
 
 
 
 
 
Occasional prolonged submersion
 
 
 
 
 
 
 
 
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


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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Last modified: 02.03.15 14:04