The purpose of this document is to provide general information on the definitions of NEMA
Enclosure Types to architects, engineers, installers, inspectors and other interested parties.
Important Note: NEMA Ratings are maintained through testing and certification. Correlation
to the IP ratings does not confirm the IP code assigned on a product or enclosure has been
tested or is under a certification program.
Definitions
In Non-Hazardous Locations, the specific enclosure Types, their applications, and the
environmental conditions they are designed to protect against, when completely and
properly installed, are as follows:
Type 1 - Enclosures constructed for indoor use to provide a degree of protection to
personnel against incidental contact with the enclosed equipment and to provide a degree of
protection against falling dirt.
Type 2 - Enclosures constructed for indoor use to provide a degree of protection to
personnel against incidental contact with the enclosed equipment, to provide a degree of
protection against falling dirt, and to provide a degree of protection against dripping and light
splashing of liquids.
Type 3 - Enclosures constructed for either indoor or outdoor use to provide a degree of
protection to personnel against incidental contact with the enclosed equipment; to provide a
degree of protection against falling dirt, rain, sleet, snow, and windblown dust; and that will
be undamaged by the external formation of ice on the enclosure.
Type 3R - Enclosures constructed for either indoor or outdoor use to provide a degree of
protection to personnel against incidental contact with the enclosed equipment; to provide a
degree of protection against falling dirt, rain, sleet, and snow; and that will be undamaged by
the external formation of ice on the enclosure.
Type 3S - Enclosures constructed for either indoor or outdoor use to provide a degree of
protection to personnel against incidental contact with the enclosed equipment; to provide a
degree of protection against falling dirt, rain, sleet, snow, and windblown dust; and in which
the external mechanism(s) remain operable when ice laden.
Type 4 - Enclosures constructed for either indoor or outdoor use to provide a degree of
protection to personnel against incidental contact with the enclosed equipment; to provide a
degree of protection against falling dirt, rain, sleet, snow, windblown dust, splashing water,
and hose-directed water; and that will be undamaged by the external formation of ice on the
enclosure.
Type 4X - Enclosures constructed for either indoor or outdoor use to provide a degree of
protection to personnel against incidental contact with the enclosed equipment; to provide a
degree of protection against falling dirt, rain, sleet, snow, windblown dust, splashing water,
hose-directed water, and corrosion; and that will be undamaged by the external formation of
ice on the enclosure.
Type 5 - Enclosures constructed for indoor use to provide a degree of protection to
personnel against incidental contact with the enclosed equipment; to provide a degree of
protection against falling dirt; against settling airborne dust, lint, fibers, and flyings; and to
provide a degree of protection against dripping and light splashing of liquids.
Type 6 - Enclosures constructed for either indoor or outdoor use to provide a degree of
protection to personnel against incidental contact with the enclosed equipment; to provide a
degree of protection against falling dirt; against hose-directed water and the entry of water
during occasional temporary submersion at a limited depth; and that will be undamaged by
the external formation of ice on the enclosure.
Type 6P - Enclosures constructed for either indoor or outdoor use to provide a degree of
protection to personnel against incidental contact with the enclosed equipment; to provide a
degree of protection against falling dirt; against hose-directed water and the entry of water
during prolonged submersion at a limited depth; and that will be undamaged by the external
formation of ice on the enclosure.
Type 12 - Enclosures constructed (without knockouts) for indoor use to provide a degree of
protection to personnel against incidental contact with the enclosed equipment; to provide a
degree of protection against falling dirt; against circulating dust, lint, fibers, and flyings; and
against dripping and light splashing of liquids.
Type 12K - Enclosures constructed (with knockouts) for indoor use to provide a degree of
protection to personnel against incidental contact with the enclosed equipment; to provide a
degree of protection against falling dirt; against circulating dust, lint, fibers, and flyings; and
against dripping and light splashing of liquids.
Type 13 - Enclosures constructed for indoor use to provide a degree of protection to
personnel against incidental contact with the enclosed equipment; to provide a degree of
protection against falling dirt; against circulating dust, lint, fibers, and flyings; and against the
spraying, splashing, and seepage of water, oil, and noncorrosive coolants.
Table 2-1
[From NEMA 250-1997]
Comparison of Specific Applications of Enclosures
for Indoor Nonhazardous Locations
Type of Enclosure
Provides a Degree of Protection Against the
Following Environmental Conditions
1 * 2 * 4 4X 5 6 6P 12 12K 13
Incidental contact with the enclosed equipment X X X X X X X X X X
Falling dirt X X X X X X X X X X
Falling liquids and light splashing ... X X X X X X X X X
Circulating dust, lint, fibers, and flyings ** ... ... X X ... X X X X X
Settling airborne dust, lint, fibers, and flyings ** ... ... X X X X X X X X
Hosedown and splashing water ... ... X X ... X X ... ... ...
Oil and coolant seepage ... ... ... .. ... ... ... X X X
Oil or coolant spraying and splashing ... ... ... ... ... ... ... ... ... X
Corrosive agents ... ... ... X ... ... X ... ... ...
Occasional temporary submersion ... ... ... ... ... X X ... ... ...
Occasional prolonged submersion ... ... ... ... ... ... X ... ... ...
* These enclosures may be ventilated.
** These fibers and flyings are nonhazardous materials and are not considered Class III type ignitable fibers or combustible flyings. For
Class III type ignitable fibers or combustible flyings see the National Electrical Code, Article 500.
Table 2-2
[From NEMA 250-1997]
Comparison of Specific Applications of Enclosures
for Outdoor Nonhazardous Locations
Type of Enclosure
Provides a Degree of Protection Against the
Following Environmental Conditions
3 3R* 3S 4 4X 6 6P
Incidental contact with the enclosed equipment X X X X X X X
Rain, snow, and sleet ** X X X X X X X
Sleet *** ... ... X ... ... ... ...
Windblown dust, lint, fibers, and flyings X ... X X X X X
Hosedown ... ... ... X X X X
Corrosive agents ... ... ... ... X ... X
Occasional temporary submersion ... ... ... ... ... X X
Occasional prolonged submersion ... ... ... ... ... ... X
* These enclosures may be ventilated.
** External operating mechanisms are not required to be operable when the enclosure is ice covered.
*** External operating mechanisms are operable when the enclosure is ice covered.
Page 4 of 6
In Hazardous Locations, when completely and properly installed and maintained, Type 7
and 10 enclosures are designed to contain an internal explosion without causing an external
hazard. Type 8 enclosures are designed to prevent combustion through the use of oilimmersed
equipment. Type 9 enclosures are designed to prevent the ignition of combustible
dust.
Type 7 - Enclosures constructed for indoor use in hazardous locations classified as Class I,
Division 1, Groups A, B, C, or D as defined in NFPA 70.
Type 8 - Enclosures constructed for either indoor or outdoor use in hazardous locations
classified as Class I, Division 1, Groups A, B, C, and D as defined in NFPA 70.
Type 9 - Enclosures constructed for indoor use in hazardous locations classified as Class II,
Division 1, Groups E, F, or G as defined in NFPA 70.
Type 10 - Enclosures constructed to meet the requirements of the Mine Safety and Health
Administration, 30 CFR, Part 18.
Table SA-1
[From NEMA 250-1997]
Comparison of Specific Applications of Enclosures
for Indoor Hazardous Locations
(If the installation is outdoors and/or additional protection is required by
Table 2-1 and Table 2-2, a combination-type enclosure is required)
Provides a Degree of Protection Against
Atmospheres Typically Containing
Enclosure Types 7 and
8, Class I Groups **
Enclosure Type 9
Class II Groups
(See NFPA 497M for Complete Listing)
Class A B C D E F G 10
Acetylene I X ... ... ... ... ... ... ...
Hydrogen, manufactured gas I ... X ... ... ... ... ... ...
Diethyl ether, ethylene, cyclopropane I ... ... X ... ... ... ... ...
Gasoline, hexane, butane, naphtha, propane,
acetone, toluene, isoprene
I ... ... ... X ... ... ... ...
Metal dust II ... ... ... ... X ... ... ...
Carbon black, coal dust, coke dust II ... ... ... ... ... X ... ...
Flour, starch, grain dust II ... ... ... ... ... ... X ...
Fibers, flyings * III ... ... ... ... ... ... X ...
Methane with or without coal dust MSHA ... ... ... ... ... ... ... X
* For Class III type ignitable fibers or combustible flyings see the National Electrical Code, Article 500.
** Due to the characteristics of the gas, vapor, or dust, a product suitable for one Class or Group may not be suitable for another Class or
Group unless marked on the product.
Page 5 of 6
Correlation Between NEMA Enclosure Type Numbers and IEC
Enclosure Classification Designations
IEC Publication 60529 Classification of Degrees of Protection Provided by Enclosures provides
a system for specifying the enclosures of electrical equipment on the basis of the degree of
protection provided by the enclosure. IEC 60529 does not specify degrees of protection
against mechanical damage of equipment, risk of explosions, or conditions such as moisture
(produced for example by condensation), corrosive vapors, fungus, or vermin. The NEMA
Standard for Enclosures for Electrical Equipment does test for environmental conditions such
as corrosion, rust, icing, oil, and coolants. For this reason, and because the test and
evaluations for other characteristics are not identical, the IEC Enclosure Classification
Designations cannot be exactly equated with the enclosure Type numbers in this Standard.
The IEC designation consists of the letters IP followed by two numerals. The first characteristic
numeral indicates the degree of protection provided by the enclosure with respect to persons
and solid foreign objects entering the enclosure. The second characteristic numeral indicates
the degree of protection provided by the enclosure with respect to the harmful ingress of water.
Table A-1 provides a correlation of the enclosure Type numbers in this Standard to the IEC
Enclosure Classification Designations (IP Codes). The enclosure type numbers meet or
exceed the test requirements for the associated IEC Classification; for this reason Table A-1
cannot be used to convert from IEC Classifications to enclosure Type numbers.
Table A-1
[From NEMA 250-1997]
Conversion of Enclosure Type numbers to IEC Classification Designations
Cannot be used to convert IEC Classification Designations
to NEMA Type numbers
Enclosure
Type Number
IEC Enclosure
Classification Designation
1 IP10
2 IP11
3 IP54
3R IP54
3S IP54
4 and 4X IP55 & IP56
5 IP52
6 AND 6P IP67
12 AND 12K IP52
13 IP54
This comparison is based on tests specified in IEC Publication 60529.
NEMA/IEC Correlation
CertifiGroup Inc
919-466-9238
May 2003
Page 6 of 6
IP Ratings and Protection Levels
And Test Equipment Identification
As defined by IEC-60529
· Degrees of Ingress Protection against solid foreign objects IP1X to IP6X
· Degrees of Ingress Protection against water IPX1 to IPX8
· Degrees of Ingress Protection against hazardous parts Suffix A-D
· Supplemental Ingress Protection factors Suffix H, M, S, & W
· Degrees of Ingress Protection against solid foreign objects = IP1X to IP6X
: 50 mm sphere Impact IP1X
: Jointed Finger Probe IP2X
: Test Rod, 2.5 mm diameter IP3X
: Test Rod, 1.0 mm diameter IP4X
: Dust Test w/ or w/o negative pressure IP5X
: Dust Test w/ negative pressure IP6X
· Degrees of Ingress Protection against water = IPX1 to IPX8
: Drip Box & Turntable IPX1
: Drip Box with tilt support IPX2
: Oscillating Spray Tester Handheld Spray Nozzle IPX3
: Oscillating Spray Tester Handheld Spray Nozzle IPX4
: Jet Nozzle w/ 6.3 mm tip IPX5
: Jet Nozzle w/ 12.5 mm tip & Pump or Water Tank System IPX6
: Enclosure is immersed in water standardized conditions of pressure IPX7
and time.
: Enclosure is continuously immersed in water under conditions which IPX8
shall be agreed between manufacturer and user but which are more severe
than for numeral 7.
· Degrees of Ingress Protection against hazardous parts = Suffix A-D
: 50 mm sphere + Creepage & Clearance Keys Suffix A
: Jointed Finger Probe & Clearance Keys Suffix B
: Test Rod, 2.5 mm diameter & Clearance Keys Suffix C
: Test Rod, 1.0 mm diameter & Clearance Keys Suffix D
· Supplemental Ingress Protection factors = Suffix H, M, S, & W
: High Voltage Apparatus Suffix H
: Ingress protection from water with moving parts in motion Suffix M
: Ingress protection from water with moving parts stationary Suffix S
: Special weather equipment – based on special product features Suffix W
