The Association of Electrical Equipment
and Medical Imaging Manufacturers
Environmental Conditions
and the Appropriate:
ENCLOSURE TYPES
The Association of Electrical Equipment
and Medical Imaging Manufacturers
Understanding the Environment
Indoors / Outdoors
Water -- Drip / Rain / Hose / Submersion / Ice
Dust -- Settling, Circulating, or Windblown Dust
Corrosive Liquids / Oil / Noncorrosive Liquids
Hazardous Location -- Gas / Combustible Dust
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and Medical Imaging Manufacturers
•Common To All Enclosures
Provide A Degree Of Protection To Personnel
Against Incidental Contact With The Enclosed
Equipment
Rod Test: NEMA 1, 2, 3R
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and Medical Imaging Manufacturers
Definitions
•Driptight  Falling dirt or moisture will not enter the
enclosure
•Dusttight  Circulating or airborne dust will not enter the
enclosure
•Rainproof  Exposure to beating rain will not interfere with
the operation of the apparatus or result in wetting
of live parts and wiring within the enclosure
The Association of Electrical Equipment
and Medical Imaging Manufacturers
Definitions
•Raintight  Exposure to beating rain will not result in
entrance of water
•Watertight  Water will not enter enclosure when subjected to
a stream of water
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and Medical Imaging Manufacturers
Type 1
•Indoor Use
•General Purpose (Not
Exposed To Unusual
Conditions)
•Degree of
Protection From
Falling Dirt
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and Medical Imaging Manufacturers
Type 2
•Indoor Use
•Degree Of
Protection From:
 Falling Dirt
 Dripping NonCorrosive Liquid
 Light Splashing
of NonCorrosive Liquid
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and Medical Imaging Manufacturers
Type 3
•Indoor or Outdoor Use
•Degree of Protection From:
 Falling Dirt, Rain, Sleet, and Snow
 Windblown Dust
•Undamaged by the External
Formation of Ice.
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and Medical Imaging Manufacturers
Type 3R
•Indoor or Outdoor Use
•Degree of Protection
From:
 Falling Dirt, Rain, Sleet,
and Snow
•Not Dustproof,
Snowproof, or Sleetproof
•Undamaged by the
External Formation of Ice
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and Medical Imaging Manufacturers
Type 3S
•Indoor or Outdoor Use
•Degree of Protection
From:
 Falling Dirt, Rain,
Sleet, Snow, and
Windblown Dust
•External
Mechanism(s) remain
Operable When Ice
Laden
The Association of Electrical Equipment
and Medical Imaging Manufacturers
Type 4
•Indoor or Outdoor Use
•Degree of Protection
From:




Windblown Dust and Rain
Splashing Water
Hose Directed Water
Undamaged by the
External Formation of Ice
The Association of Electrical Equipment
and Medical Imaging Manufacturers
Type 4X
•Indoor or Outdoor Use
•Degree of Protection From:
 Windblown Dust and
Rain
 Splashing Water
 Hose Directed Water
 Damage from External
Ice Formation
 Corrosion Resistive
The Association of Electrical Equipment
and Medical Imaging Manufacturers
Type 5
•Indoor Use
•Degree of Protection
From:
 Falling Dirt, Settling
Airborne Dust, Lint,
Fibers, and Flyings
 Dripping and Light
Splashing of
Noncorrosive Liquids
The Association of Electrical Equipment
and Medical Imaging Manufacturers
Type 6
•Indoor or Outdoor Use
•Degree of Protection From:
 Falling Dirt
 Hose Directed Water
 Damage From External Ice
Formation
 Entry of Water During
Occasional Temporary
Submersion at a Limited
Depth
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and Medical Imaging Manufacturers
Type 6P
•Indoor or Outdoor Use
•Degree of Protection From:
 Falling Dirt
 Hose Directed Water
 Damage From External Ice Formation
 Entry of Water During Prolonged
Submersion at a Limited Depth
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and Medical Imaging Manufacturers
Type 7
Indoor use in
locations classified
as Class I, Groups A,
B, C, or D, as defined
in the NEC®.
Protection against
Hazardous Location
atmospheres
containing Gases
and Vapors.
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and Medical Imaging Manufacturers
Type 8
Indoor or Outdoor use in locations
classified as Class I, Groups A, B, C,
or D, as defined in the NEC®.
Protection against Hazardous
Location atmospheres containing
Gases and Vapors.
Arcing contacts, connections, … are
immersed in oil in order to confine
ignition source.
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Type 9
Indoor use in locations
classified as Class II,
Groups E, F, or G, as
defined in the NEC®.
Protection against
Hazardous Location
atmospheres containing
Dust.
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Type 10
Capable of meeting the
requirements of the (MSHA) Mine
Safety and Health Administration, 30
C.F.R., Part 18.
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Type 12
Indoor use primarily to provide a
degree of protection against:
• Circulating Dust
• Falling Dirt
• Dripping Noncorrosive Liquid
• Circulating Lint, Fibers and
Flyings (Nonhazardous and not considered Class
III Type ignitable fibers or flyings)
Type 12K
Type 12 with Knockouts
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and Medical Imaging Manufacturers
Type 13
Indoor or Outdoor use
primarily to provide a
degree of protection
against:
• Dust
• Spraying of Water, Oil, and
Noncorrosive Coolant
• Oil and Coolant Seepage
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and Medical Imaging Manufacturers
Comparison of Indoor Enclosure
Applications
Condition of Protection
Falling Dirt
Falling Liquids and Light Splashings
Circulating dust, lint, fibers, & flyings
Settling airborne dust, lint, fibers & flyings*
Hosedown and Splashing water
Oil and Coolant seepage
Oil or Coolant spraying and splashing
Corrosive Agents
Occasional Temporary Submersion
Occasional Prolonged Submersion
1
X
----------
2
X
X
---------
4
X
X
X
X
X
------
Enclosure Type
4X 5 6 6P 12(K)
X X X X
X
X X X X
X
X -- X X
X
X X X X
X
X -- X X
--- -- -- -X
-- -- -- --X -- -- X
--- -- X X
--- -- -- X
--
* These fibers and flyings are nonhazardous materials and are not
considered Class III type ignitable fibers or combustibles flyings
Table: NEMA 250
13
X
X
X
X
-X
X
----
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and Medical Imaging Manufacturers
Comparison of Outdoor
Enclosure Applications
Condition of Protection
Rain, snow, sleet
Sleet (External Operating Mech. Operable w/ ice)
Windblown dust
Hosedown
Corrosive Agents
3
X
-X
---
Enclosure Type
3R 3S 4 4X
X
X
X X
-X
---X
X X
--X X
---- X
Table: NEMA 250
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Comparison of Indoor Enclosure
Applications for Hazardous Locations
Atmosphere Containing:
Acetylene
Hydrogen, manufactured gas
Diethel ether, ethylene, cyclopropane
Gasoline, hexane, butane, naphtha,
propane,acetone,toluene, isoprene
Metal dust
Carbon black, coal dust, coke dust
Flour, starch, grain dust
Fiber flyings
Methane with or without coal dust
Type 7 & 8
Class A B C D
I
I
I
I
II
II
II
III
Type 9
E F G
10
X -- -- -- -- -- --- X -- -- -- -- --- -- X -- -- -- --
----
-----MSHA --
-------
-------
X
------
-X
-----
--X
----
---X
X
--
-----X
Table: NEMA 250
See NFPA 497M for complete listing of atmosphere classifications
NFPA 496, Purged and Pressurized Enclosures ..., outlines alternatives to
Type 7 & 9 Enclosures when adequate positive pressure ventilation is used.
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and Medical Imaging Manufacturers
IEC Enclosure Designations
•European System of specifying the degree
of protection provided by the enclosure.
•NEC® does not accept IP designations as
an alternative for Type ratings.
•IEC 60529 does not address mechanical
damage, risk of explosion, or corrosion.
•UL 50E and NEMA 250 do evaluate
mechanical characteristics such as corrosion,
icing, oil, …
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IEC Enclosure Designations
Example: IP10
•The IEC designation consists of the letters
IP followed by two numerals.
•The first numeral indicates the degree of
protection provided against persons and solid
foreign objects entering the enclosure.
•The second numeral indicates the degree of
protection provided against the harmful
ingress of water into the enclosure.
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and Medical Imaging Manufacturers
Conversion of NEMA Types to IEC IP
Designations
IP
First
Character
IP
Second
Character
NEMA Enclosure Type
1
2
3
3R
3S
4
4X
5
6
6P
12
12K
13
IP0_
IP1_
IP2_
IP3_
IP4_
IP5_
IP6_
IP_0
IP_1
IP_2
IP_3
IP_4
IP_5
IP_6
IP_7
IP_8
A B A B A B A B A B A B A B A B A B A B A B A B A B
A = A shaded block in the “A” column indicates that the NEMA Enclosure Type exceeds the
requirements for the respective IEC 60529 IP First Character Designation. The IP First Character
Designation is the protection against access to hazardous parts and solid foreign objects.
B = A shaded block in the “B” column indicates that the NEMA Enclosure Type exceeds the
requirements for the respective IEC 60529 IP Second Character Designation. The IP Second
Character Designation is the protection against the ingress of water.
(This Table cannot be used to convert IEC IP Designations to NEMA Enclosure Types)
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and Medical Imaging Manufacturers
Understanding the Enclosure Conversion Table
EXAMPLE OF TABLE USE
An IEC IP 45 Enclosure Rating is specified. What NEMA Type Enclosures meet and exceed the IP 45 rating?
Referencing the first character, 4, in the IP rating and the row designated “IP4_” in the leftmost column in the table;
the blocks in Column “A” for NEMA Types 3, 3S, 4, 4X, 5, 6, 6P, 12, 12K and 13 are shaded. These NEMA
ratings meet and exceed the IEC protection requirements against access to hazardous parts and solid foreign objects.
Referencing the second character, 5, in the IP rating and the row designated “IP_5” in the rightmost column in the
table; the blocks in Column “B” for NEMA Types 3, 3S, 4, 4X, 6 and 6P are shaded. These NEMA ratings meet
and exceed the IEC requirements for protection against the ingress of water. The absence of shading in Column “B”
beneath the “NEMA Enclosure Type 5” indicates that Type 5 does not meet the IP 45 protection requirements
against the ingress of water. Likewise the absence of shading in Column “B” for NEMA Type 12, 12K and 13
enclosures indicates that these enclosures do not meet the IP 45 requirements for protection against the ingress of
water. Only Types 3, 3S, 4, 4X, 6 and 6P have both Column “A” in the “IP4_” row and Column “B” in the “IP_5”
row shaded and could be used in an IP45 application.
The NEMA Enclosure Type 3 not only meets the IP 45 Enclosure Rating, but also exceeds the IEC requirements
because the NEMA Type requires an outdoor corrosion test; a gasket aging test; a dust test; an external icing test;
and no water penetration in the rain test. Slight differences exist between the IEC and NEMA test methods, but the
IEC rating permits the penetration of water if “it does not deposit on insulation parts, or reach live parts.” The IEC
rating does not require a corrosion test; gasket aging test; dust test or external icing test. Because the NEMA ratings
include additional test requirements, this table cannot be used to select IP Designations for NEMA rated enclosure
specifications.
Since the IEC protection requirements become more stringent with increasing IP character value, once a NEMA
rating meets the requirements for an IP designation, it will also meet the requirements for all lower IP designations.
This is apparent from the shaded areas shown in the table.
(The Table cannot be used to convert IEC IP Designations to NEMA Enclosure Types)
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Multiple Types on Enclosure
Type 3, 3R, 4X, 5, 12
Stainless Steel or other materials approved
for the use (Corrosion Protection)
Drain Plug (Remove for Type 3R)
Gasketing (Dust and Water Protection)
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Power Outlet
UL 231 - Power Outlet
-Water Splash Test
-GFCI Requirements
NEC® Branch Circuits
590.4 Temporary Installations
555.19(A)(3) Marinas and
Boatyards
551.78(A) Recreational Vehicle
Parks
The Association of Electrical Equipment
and Medical Imaging Manufacturers
•More Information?
UL “White” Book
Electrical Equipment For Use In Ordinary Locations, Page 133
Hazardous Locations Equipment Directory, Page 101
NEMA
NEMA Standard 250-2013
Global Publications (800) 854-7179