NEMA EN P1-2020
NEMA 250 Enclosure Types
Published by
National Electrical Manufacturers Association
1300 North 17th Street, Suite 900
Rosslyn, Virginia 22209
www.nema.org
© 2020 National Electrical Manufacturers Association. All rights including translation into other languages,
reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary
and Artistic Works, and the International and Pan American Copyright Conventions.
NEMA EN P1-2020
Page 2
Disclaimer
The guidelines presented in a NEMA Standards publication are considered technically sound at the time
they are approved for publication. They are not a substitute for a product seller’s or user’s own judgment
with respect to the particular product referenced in the Standard or guideline, and NEMA does not
undertake to guarantee the performance of any individual manufacturer’s products by virtue of this
Standard or guide. Thus, NEMA expressly disclaims any responsibility for damages arising from the use,
application, or reliance by others on the information contained in these Standards or guidelines.
© 2020 National Electrical Manufacturers Association
NEMA EN P1-2020
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Foreword
This NEMA white paper is completely based on NEMA 250 Enclosures for Electrical Equipment (1000
Volts Maximum). In the preparation of this white paper, input of users and other interested parties has
been sought and evaluated. This publication will be periodically reviewed by the Enclosures Section of
the NEMA Building Infrastructure Division.
Proposed or recommended revisions should be submitted to:
NEMA Technical Operations Department
National Electrical Manufacturers Association
1300 North 17th Street, Suite 900
Rosslyn, Virginia 22209
This Standard was developed by the NEMA Enclosure Section of the Building Infrastructure Division.
Section approval of the Standard does not necessarily imply that all section Members voted for its
approval or participated in its development. At the time it was approved, the Enclosure Section was
composed of the following Members:
ABB, Inc.
Allied Moulded Products, Inc.
AmeriTex Machine and Fabrication, LLC.
Arlington Industries, Inc.
Atkore International
Boltswitch, Inc.
Eaton
Emerson Automation Solutions
Hubbell Incorporated
IPEX USA, LLC.
Legrand, North America
Millbank Manufacturing Company
nVent, Hoffman Enclosures Inc.
Rittal North America LLC
Robroy Industries, Inc.
Schneider Electric
Siemens Industry, Inc.
Snake Tray
Space Age Electronics
Memphis, TN
Bryan, OH
Willis, TX
Scranton, PA
Harvey, IL
Crystal Lake, IL
Cleveland, OH
Rosemont, IL
Shelton, CT
Pineville, NC
West Hartford, CT
Kansas City, MO
St. Louis Park, MN
Urbana, OH
Verona, PA
Boston, MA
Norcross, GA
Bay Shore, NY
Sterling, MA
© 2020 National Electrical Manufacturers Association
NEMA EN P1-2020
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Scope
The purpose of this document is to provide general information on the definitions of NEMA enclosure
types, a guide for comparing specific applications of enclosures, and a comparison between NEMA
enclosure type numbers, and ANSI/IEC enclosure classification designations. The document is
intended for use by architects, engineers, installers, inspectors, and other interested parties. For more
detailed and complete information, please refer to NEMA 250-2018 Enclosures for Electrical
Equipment (1000 Volts Maximum).
NEMA Type Ratings
The following definitions have been taken from the NEMA 250.
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 access to hazardous parts and provide a degree of protection of the equipment
inside the enclosure against ingress of solid foreign objects (falling dirt).
Type 2
Enclosures constructed for indoor use to provide a degree of protection for personnel
against access to hazardous parts; provide a degree of protection of the equipment inside
the enclosure against ingress of solid foreign objects (falling dirt); and, provide a degree of
protection from harmful effects on the equipment due to the ingress of water (dripping and
light splashing).
Type 3
Enclosures constructed for either indoor or outdoor use to provide a degree of protection
for personnel against access to hazardous parts; provide a degree of protection of the
equipment inside the enclosure against ingress of solid foreign objects (falling dirt and
windblown dust); provide a degree of protection from harmful effects on the equipment due
to the ingress of water (rain, sleet, snow); 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
for personnel against access to hazardous parts; provide a degree of protection of the
equipment inside the enclosure against ingress of solid foreign objects (falling dirt); provide
a degree of protection from harmful effects on the equipment due to the ingress of water
(rain, sleet, 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
for personnel against access to hazardous parts; provide a degree of protection of the
equipment inside the enclosure against ingress of solid foreign objects (falling dirt and
windblown dust); provide a degree of protection from harmful effects on the equipment due
to the ingress of water (rain, sleet, snow); and, for which the external mechanism(s) remain
operable when ice-laden.
Type 3X
Enclosures constructed for either indoor or outdoor use to provide a degree of protection
for personnel against access to hazardous parts; provide a degree of protection of the
equipment inside the enclosure against ingress of solid foreign objects (falling dirt and
windblown dust); provide a degree of protection from harmful effects on the equipment due
to the ingress of water (rain, sleet, snow); that provides an increased level of protection
against corrosion and that will be undamaged by the external formation of ice on the
enclosure.
Type 3RX
Enclosures constructed for either indoor or outdoor use to provide a degree of protection
for personnel against access to hazardous parts; provide a degree of protection of the
© 2020 National Electrical Manufacturers Association
NEMA EN P1-2020
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equipment inside the enclosure against ingress of solid foreign objects (falling dirt); provide
a degree of protection from harmful effects on the equipment due to the ingress of water
(rain, sleet, snow); that will be undamaged by the external formation of ice on the enclosure
that provides an increased level of protection against corrosion.
Type 3SX
Enclosures constructed for either indoor or outdoor use to provide a degree of protection
for personnel against access to hazardous parts; provide a degree of protection of the
equipment inside the enclosure against ingress of solid foreign objects (falling dirt and
windblown dust); provide a degree of protection from harmful effects on the equipment due
to the ingress of water (rain, sleet, snow); that provides an increased level of protection
against corrosion; and for which the external mechanism(s) remain operable when iceladen.
Type 4
Enclosures constructed for either indoor or outdoor use to provide a degree of protection
for personnel against access to hazardous parts; provide a degree of protection of the
equipment inside the enclosure against ingress of solid foreign objects (falling dirt and
windblown dust); provide a degree of protection from harmful effects on the equipment due
to the ingress of water (rain, sleet, snow, 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
for personnel against access to hazardous parts; provide a degree of protection of the
equipment inside the enclosure against ingress of solid foreign objects (falling dirt and
windblown dust); provide a degree of protection from harmful effects on the equipment due
to the ingress of water (rain, sleet, snow, splashing water, and hose directed water); that
provides an increased level of protection against 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 for personnel
against access to hazardous parts; provide a degree of protection of the equipment inside
the enclosure against ingress of solid foreign objects (falling dirt and settling dust, lint,
fibers, and flyings); and, provide a degree of protection from harmful effects on the
equipment due to the ingress of water (dripping and light splashing).
Type 6
Enclosures constructed for either indoor or outdoor use to provide a degree of protection
forpersonnel against access to hazardous parts; provide a degree of protection of the
equipment inside the enclosure against ingress of solid foreign objects (falling dirt); provide
a degree of protection from harmful effects on the equipment due to the ingress of water
(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
for personnel against access to hazardous parts; provide a degree of protection of the
equipment inside the enclosure against ingress of solid foreign objects (falling dirt); provide
a degree of protection from harmful effects on the equipment due to the ingress of water
(hose directed water and the entry of water during prolonged submersion at a limited
depth); that provides an increased level of protection against corrosion 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
for personnel against access to hazardous parts; provide a degree of protection of the
equipment inside the enclosure against ingress of solid foreign objects (falling dirt and
circulating dust, lint, fibers, and flyings); provide a degree of protection from harmful effects
© 2020 National Electrical Manufacturers Association
NEMA EN P1-2020
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on the equipment due to the ingress of water (dripping and light splashing) and provide a
degree of protection against light splashing and seepage of oil and non-corrosive coolants.
Type 12K
Enclosures constructed (with knockouts) for indoor use to provide a degree of protection for
personnel against access to hazardous parts; provide a degree of protection of the
equipment inside the enclosure against ingress of solid foreign objects (falling dirt and
circulating dust, lint, fibers, and flyings); and, provide a degree of protection from harmful
effects on the equipment due to the ingress of water (dripping and light splashing) and
provide a degree of protection against light splashing and seepage of oil and non-corrosive
coolants.
Type 13
Enclosures constructed for indoor use to provide a degree of protection for personnel
against access to hazardous parts; to provide a degree of protection of the equipment
inside the enclosure against ingress of solid foreign objects (falling dirt and circulating dust,
lint, fibers, and flyings); to provide a degree of protection from harmful effects on the
equipment due to the ingress of water (dripping and light splashing); and, to provide a
degree of protection against the spraying, splashing, and seepage of oil and non-corrosive
coolants.
In hazardous locations, when completely and properly installed and maintained, Type 7 enclosure is
designed to contain an internal explosion without causing an external hazard. Type 9 enclosures are
designed to prevent the ignition of combustible dust.
Table 2-1, NEMA 250-2018
Comparison of Specific Applications of Enclosures for Indoor Locations
Type of Enclosure
Provides a Degree of Protection against
the Following Conditions
1
2
4
4X
5
6
6P
12
12K
13
Access to hazardous parts
X
X
X
X
X
X
X
X
X
X
Ingress of solid foreign objects (falling dirt)
Ingress of water (dripping and light
splashing)
Ingress of solid foreign objects (circulating
dust, lint, fibers, and flyings **)
Ingress of solid foreign objects (settling dust,
lint, fibers, and flyings **)
Ingress of water (hosedown and splashing
water)
Oil and coolant seepage
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
X
X
X
X
X
X
…
…
X
X
…
X
X
…
…
…
…
…
…
..
…
…
…
X
X
X
Oil or coolant spraying and splashing
…
…
…
…
…
…
…
…
…
X
Corrosive agents
Ingress of water (occasional temporary
submersion)
Ingress of water (occasional prolonged
submersion)
...
...
...
...
...
...
X
...
...
...
...
X
X
X
...
...
...
...
...
...
...
...
...
...
...
...
X
...
...
...
© 2020 National Electrical Manufacturers Association
NEMA EN P1-2020
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Type 7
Explosion-proof enclosures demonstrating compliance with the requirements of
ANSI/UL 1203 for use in hazardous (classified) locations classified as Class I, Division 1,
Groups A, B, C, or D as defined in ANSI/NFPA 70.
Type 9
Dust-ignition-proof enclosures demonstrating compliance with the requirements of ANSI/UL
1203 for use in hazardous (classified) locations classified as Class II, Division 1, Groups E,
F, or G as defined in ANSI/NFPA 70.
Specific Type Ratings
The following tables are guides for comparing specific applications of enclosures.
**
These fibers and flyings are not considered Class III type ignitable fibers or combustible flyings. For
Class III type ignitable fibers or flyings, see the NEC, Article 500.5(D).
Table 2-2, NEMA 250-2018
Comparison of Specific Applications of Enclosures for Indoor & Outdoor Locations
Provides a Degree of Protection Against
the Following Conditions
Access to hazardous parts
Ingress of solid foreign objects (falling dirt)
Ingress of water (dripping and light
splashing)
Ingress of water (rain, snow, and sleet**)
Sleet***
Ingress of solid foreign objects (windblown
dust, lint, fibers, and flyings****)
Ingress of water (hosedown and splashing
water)
Corrosive agents
Ingress of water (occasional temporary
submersion)
Ingress of water (occasional prolonged
submersion)
Type of Enclosure
3
X
X
X
3X
X
X
X
3R
X
X
X
3RX
X
X
X
3S 3SX
X
X
X
X
X
X
4
X
X
X
4X
X
X
X
6
X
X
X
6P
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
...
...
...
X
...
...
...
X
...
...
...
X
...
...
X
X
X
...
...
...
...
...
...
...
...
...
X
** 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. See subsection 5.6 of
NEMA 250-2018.
**** These fibers and flyings are not considered Class III type ignitable fibers or combustible flyings. For
Class III type ignitable fibers or flyings see the NEC, Article 500.5(D).
© 2020 National Electrical Manufacturers Association
NEMA EN P1-2020
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Ancillary Ratings
In addition to type designations, the following ancillary conditions can be evaluated and marked. The
ancillary ratings are optional add-ons to the basic type ratings.
Pressure Wash (PW)
Enclosures constructed for exterior cleaning with high-pressure power washers and tested in accordance
with Section 5.15 of NEMA 250. The PW ancillary rating may be appended only to the following ratings: 3,
3X, 3S, 3SX, 4, 4X, 6, 6P, 12, 12X, 13.
§
© 2020 National Electrical Manufacturers Association