NEMA 250

NEMA 250 Enclosure Types and Ratings

Current designation: ANSI/NEMA EN 10250-2024, Enclosures for Electrical Equipment (1000 Volts Maximum)

Maintained by Giorgi Gaprindashvili Published July 3, 2026 Updated September 18, 2026 Editorial check September 2026

Choose by the exposure, not the number

Start with the real environment: dry indoor, dust or dripping liquid, rain, washdown, corrosion, submersion or a hazardous location. The Type number is a tested category, not a quality score.

Key facts

Current designation: ANSI/NEMA EN 10250-2024
Former designation: ANSI/NEMA 250-2020; the 2024 document is its revision and redesignation
Full title: Enclosures for Electrical Equipment (1000 Volts Maximum)
Published by: NEMA (National Electrical Manufacturers Association)
Scope: Enclosures for electrical equipment rated not more than 1000 V
Type groups: Indoor Types 1, 2, 5, 12, 12K and 13; indoor/outdoor Types 3-series, 4-series and 6-series; hazardous-location Types 7 and 9
Certification: NEMA publishes the requirements but does not certify products; third-party listing or certification is a separate product evaluation
IP relationship: NEMA Type and IEC IP codes overlap only partly; a reverse IP-to-NEMA conversion is not valid

NEMA 250 is now ANSI/NEMA EN 10250

The enclosure standard most engineers and product listings still call NEMA 250 was revised and redesignated in 2024. Its current record is ANSI/NEMA EN 10250-2024. Keeping NEMA 250 in the page title is useful because it remains the familiar search and industry term, but a current specification or compliance file should identify the edition actually being applied.

Searches for a NEMA 250 PDF often surface old charts and summaries. The current copyrighted standard is available through the official ANSI/NEMA record as a paid PDF. This page is a selection-oriented explanation, not a reproduction of the test procedures, construction clauses or acceptance criteria.

What EN 10250 covers and what it does not

ANSI/NEMA EN 10250 covers enclosures for electrical equipment rated not more than 1000 V. It groups indoor Types 1, 2, 5, 12, 12K and 13; indoor or outdoor Types 3, 3X, 3R, 3RX, 3S, 3SX, 4, 4X, 6 and 6P; and hazardous-location Types 7 and 9. The requirements supplement the applicable end-product standard rather than replacing it.

A Type rating describes protection provided by the completed enclosure under specified conditions. It does not rescue an installation with unsuitable conduit entries, open doors, missing plugs, damaged gaskets or accessories that were never evaluated with the enclosure. Manufacturer instructions and the applicable electrical code still control the installed system.

How NEMA enclosure ratings work

Each Type addresses a defined combination of environmental conditions such as falling dirt, circulating dust, rain, sleet, hose-directed water, submersion, oil or coolant, corrosion and external icing. The correct Type is the one whose tested conditions cover the real installation, not simply the largest number printed in a catalogue.

The suffixes also carry meaning. X identifies a corrosion-resistant variant within a Type family. R identifies rain-oriented variants in the Type 3 family, while S identifies versions whose external mechanisms remain operable when ice-laden. Those letters do not make unrelated Type numbers interchangeable.

NEMA Type, UL listing and CSA certification are different claims

NEMA develops the enclosure-Type requirements but does not operate a product-certification programme for the Type mark. A manufacturer can state a Type based on its conformity process, while a UL, CSA or other recognised certification mark indicates a separate third-party evaluation under the standards shown in that product's certification record.

For nonhazardous enclosures, UL 50 covers general construction and UL 50E covers environmental performance; the Canadian companion documents are CSA C22.2 No. 94.1 and No. 94.2. UL 50E does not cover hazardous-location Types 7 and 9. Always check the actual certification mark, model scope and installation instructions rather than treating the words NEMA 4X as proof of a listing that is not shown.

Why an IP rating does not convert back to a NEMA Type

IEC 60529 IP codes focus on access to hazardous parts and ingress of solids and water. NEMA enclosure Types can also address characteristics outside that two-character IP designation, including corrosion, external icing, oil or coolant exposure and construction-related requirements. The systems therefore overlap, but they are not equivalent labels.

NEMA has historically published one-way correlations from some enclosure Types to IP degrees, while also stating that an IP degree cannot be treated as an equivalent NEMA Type. Because the current-site cross-reference table has not been independently verified against the current 2024 edition, Standard Clarity withholds automatic conversion and product relabeling. Use an attributed edition-specific table only as screening evidence and verify the actual product declarations.

Most common NEMA enclosure Types

These are practical starting points, not automatic selections. Accessories, penetrations, certification scope and the end-product standard can change the requirement.

Type 1: indoor general purpose

Basic indoor protection against access to hazardous parts and falling dirt. Not intended for rain, washdown or heavy dust.

Type 3R: outdoor rain and sleet

A common ventilated outdoor choice for rain, snow and sleet where windblown-dust or hose-down protection is not required.

Type 4: hose-directed water

Indoor or outdoor protection for windblown dust, rain, splashing and hose-directed water, with external-ice requirements.

Type 4X: Type 4 plus corrosion resistance

Used where washdown and corrosive exposure both matter, subject to the material, product and certification details.

Type 12 / 12K: indoor industrial

Indoor protection against circulating dust, falling dirt and dripping non-corrosive liquids; 12K permits knockouts.

Type 13: oil and coolant spray

Indoor protection against dust, spraying water, oil and non-corrosive coolant in machinery and industrial environments.

Type 6 / 6P: submersion

For temporary or prolonged submersion under the product's evaluated conditions. Depth and duration are not chosen from the Type number alone.

NEMA enclosure ratings chart

The chart summarizes selection cues only. It does not replace the standard's complete construction, conditioning, test and marking requirements.

Higher numbers are not a ranking. Type 7 and Type 9 selections require the applicable hazardous-location product requirements, certification and code review.
Type	Location	Core protection	Typical selection cue
1	Indoor	Access to hazardous parts and falling dirt	Dry, clean general-purpose indoor equipment
2	Indoor	Type 1 protection plus dripping and light splashing	Indoor locations with occasional dripping liquid
3	Indoor / Outdoor	Rain, sleet, snow and windblown dust; external ice	Outdoor exposure where windblown dust matters
3X	Indoor / Outdoor	Type 3 conditions plus corrosion resistance	Outdoor dust and weather with corrosive exposure
3R	Indoor / Outdoor	Rain, sleet and snow; external ice	Common ventilated outdoor enclosures
3RX	Indoor / Outdoor	Type 3R conditions plus corrosion resistance	Rain-oriented outdoor use with corrosion concern
3S	Indoor / Outdoor	Type 3 weather protection with mechanisms operable when ice-laden	Outdoor equipment with external operating mechanisms
3SX	Indoor / Outdoor	Type 3S conditions plus corrosion resistance	Icing, operating mechanisms and corrosion together
4	Indoor / Outdoor	Windblown dust, rain, splashing and hose-directed water; external ice	Washdown or severe weather without a corrosion requirement
4X	Indoor / Outdoor	Type 4 conditions plus corrosion resistance	Washdown with coastal, chemical or corrosive exposure
5	Indoor	Settling airborne dust and dripping non-corrosive liquids	Dusty indoor equipment where washdown is not required
6	Indoor / Outdoor	Hose-directed water and temporary submersion; external ice	Occasional temporary submersion under evaluated conditions
6P	Indoor / Outdoor	Prolonged submersion and corrosion resistance	More severe submersion under the product's stated conditions
12 / 12K	Indoor	Circulating dust, falling dirt and dripping non-corrosive liquids	Industrial control and machinery enclosures; 12K has knockouts
13	Indoor	Dust, spraying water, oil and non-corrosive coolant	Machine-tool and industrial oil/coolant exposure
7	Hazardous (classified)	Certain gas or vapour hazardous-location conditions	Use only with the applicable certified hazardous-location product
9	Hazardous (classified)	Certain combustible-dust hazardous-location conditions	Use only with the applicable certified hazardous-location product

Tools that use this standard

NEMA enclosure type selector IP / NEMA rating decoder

Related standards

Standard	Relationship	What it means
IEC 60529 (IP code)	Overlapping ingress system	IP codes cover access, solids and water ingress. NEMA Types can add corrosion, icing, oil or coolant and other enclosure requirements, so reverse conversion is not valid.
UL 50 / UL 50E and CSA C22.2 No. 94.1 / 94.2	Third-party evaluation standards	UL 50 and CSA 94.1 address general construction; UL 50E and CSA 94.2 address environmental performance for nonhazardous enclosure Types.
NFPA 70 (NEC), 110.3(B)	Installation and use	Listed or labelled equipment is installed and used in accordance with instructions included in its listing or labelling, as also referenced by the EN 10250 scope.
NEMA IA 10030-2024	Industrial-control companion	Covers enclosure requirements for industrial control devices and systems on commercial voltages up to 750 V dc or 7200 V ac.

Official sources and related standards

ANSI/NEMA EN 10250-2024Current official standard record and PDF purchase page. UL 50ECurrent environmental-performance standard for nonhazardous enclosure Types. NEMA IA 10030-2024Current NEMA enclosure document for industrial control devices and systems.

Frequently asked questions

Is NEMA 250 still the current standard?

The familiar NEMA 250 designation was revised and redesignated in 2024. The current record is ANSI/NEMA EN 10250-2024, Enclosures for Electrical Equipment (1000 Volts Maximum). NEMA 250 remains the common industry and search term, so specifications should state the actual edition being applied.

What is NEMA 250?

NEMA 250 is the former designation of the North American enclosure-Type standard now published as ANSI/NEMA EN 10250-2024. It defines Types such as 1, 3R, 4, 4X, 6P, 12 and 13 and the construction, performance, test and marking requirements behind them.

Where can I get the official NEMA 250 PDF?

The current copyrighted document is sold through the official ANSI/NEMA record as ANSI/NEMA EN 10250-2024. Free charts can help with orientation, but they do not contain the complete test procedures, acceptance criteria or product-specific requirements.

What is the difference between NEMA 250 and UL 50E?

EN 10250 defines the NEMA enclosure-Type system and includes the complete Type scope, including hazardous-location Types 7 and 9. UL 50E covers environmental construction and performance for nonhazardous Types, while UL 50 contains general construction requirements. A UL mark indicates a separate third-party product evaluation; a NEMA Type claim alone does not prove that listing.

Is a higher NEMA Type number better?

No. NEMA Types are environmental categories, not a ladder. Type 4 is an indoor/outdoor hose-down category, Type 5 is an indoor dust category, Type 12 is an indoor industrial category and Type 6 addresses submersion. Choose the Type whose evaluated conditions match the installation.

What is the difference between NEMA 4 and 4X?

Both address indoor or outdoor exposure including windblown dust, rain, splashing and hose-directed water. Type 4X adds corrosion-resistance requirements. The enclosure material, coating, accessories and certification scope still need to match the real corrosive environment.

What is the difference between NEMA 3R and NEMA 4?

Type 3R is commonly used for outdoor rain, snow and sleet and may be ventilated. Type 4 adds stronger protection including windblown dust, splashing and hose-directed water. A 3R product should not be assumed to satisfy a Type 4 washdown requirement.

What is the difference between NEMA 12 and NEMA 4?

Type 12 is an indoor industrial category for circulating dust, falling dirt and dripping non-corrosive liquids. Type 4 is indoor or outdoor and includes windblown dust, rain, splashing and hose-directed water. Type 12 is not an outdoor or hose-down substitute for Type 4.

Can I convert an IP rating to a NEMA Type?

No universal reverse conversion exists. IP codes and NEMA enclosure Types cover overlapping but different characteristics. A published NEMA-to-IP cross-reference may be useful as attributed screening information for a specific edition, but it does not prove that a product carries the other system’s rating.

Does a NEMA rating mean the enclosure is UL listed?

No. NEMA publishes the Type requirements but does not certify products. UL, CSA and other recognised certification marks represent separate evaluations whose model scope and conditions must be checked in the certification record.

What replaced NEMA ICS 6?

For industrial control devices and systems, the current NEMA enclosure document is NEMA IA 10030-2024. It covers enclosure requirements for industrial control devices on commercial voltages up to 750 V dc or 7200 V ac. It is related to, but not a substitute for, the broader EN 10250 enclosure-Type standard.

Does EN 10250 cover hazardous locations?

Its scope includes Types 7 and 9 for hazardous (classified) locations, but selection requires the applicable hazardous-location product standard, certification, gas or dust classification and electrical-code review. A generic enclosure chart is not sufficient for that decision.

Source: ANSI/NEMA EN 10250-2024 official record. An overview for design reference - verify against the current edition before relying on it for compliance.