National Electrical Manufacturers Association (NEMA)
General purpose. For indoor protection where conditions
are not unusually severe.
Drip-tight. For indoor use. Designed to exclude falling
moisture or dirt. Particularly applicable to cooling rooms,
laundries, etc., where condensation is prevalent.
Weatherproof. For outdoor use. Designed to withstand all
normal exposure to natural elements. Controls mounted on
pullout racks for easy access. With rain hood and weather
Watertight and dust-tight. Intended for use indoors or
outdoors to protect equipment against splashing, falling, or
hose-directed water, external condensation, and water
seepage. Withstands water pressure from 1" hose nozzle, 65
gallons per minute, from distances of not less than 10 feet
for a period of five minutes.
Watertight, dust-tight, and corrosion-resistant
enclosures. Meets the same qualifications as NEMA 4 but with
added corrosion resistance.
Dust-tight. Equipped with dust-tight gaskets. Suitable
for mills and other high-dust atmospheres.
Submersible. For submerged operation under specified
pressures and time.
Enclosures for indoor Class I, Division 1 hazardous
locations with gas or vapor atmospheres. National Electrical
Code class 1 (circuit breaks in air).
Hazardous locations. National Electrical Code class 1
(circuit breaks immersed in oil).
For indoor Class II, Division I hazardous locations with
combustible dust atmospheres. National Electrical Code class
Explosion-proof. Meets U.S. Bureau of Mines requirements
for explosive atmospheres. Units that are designed to
contain gas or vapor explosions within the enclosure and
prevent ignition of the surrounding atmospheres.
Acid- or fume-resistant. Provides for immersion of
enclosed equipment in oil.
Industrial use. Excludes oils, dust, moisture, to
satisfy individual requirements.
Oil-tight and dust-tight. Intended for indoor use.
International Electrotechnical Commission (IEC)
IEC standards use a designation of IP(ab) where (a) denotes the enclosure's degree of protection against contact and ingress of solid bodies and (b) denotes the enclosure's degree of protection against ingress of water.
(a) Solids Protection
0 No special protection.
1 Protection against ingress of solid objects with a diameter greater than 50mm.
2 Protection against penetration by solid objects with a diameter greater than 12mm.
3 Protection against ingress of solid objects with a diameter greater than 2.5mm.
4 Protection against ingress of solid objects with a diameter greater than 1mm.
(b) Water Protection
0 No special protection.
1 Protection against dripping water falling vertically.
2 Protection against dripping water falling at 75° to 90° angles.