NEMA code designations for electrical enclosures.
This is a very brief guide only - no responsibility ..... etc.!

The information on this page was downloaded a while ago as a text file, the page layout is by Roger Greenwood. See the end for credits.

Type 1 - General Purpose

A General purpose enclosure is intended primarily to prevent accidental contact with the enclosed apparatus. It is suitable for general purpose applications indoors where it is not exposed to unusual service conditions.

Type 2 - Drip-Tight

A drip-tight enclosure is intended primarily to prevent accidental contact with the enclosed apparatus and, in addition, is so constructed as to exclude falling moisture or dirt.

Type 3 - Weatherproof (Weather-Resistant)

A weatherproof enclosure is intended to provide suitable protection against specified weather hazards. It is suitable for use outdoors.

Type 3R - Rain tight

A rain tight enclosure is intended primarily to meet the requirements for rain tight (definition No. 7 of appended list) apparatus. It is suitable for general applications outdoors where sleet-proof construction is not required.

Type 4 - Watertight

A watertight enclosure is designed to exclude water applied in the form of a hose stream. It is suitable for application where the apparatus may be subjected to a stream of water during cleaning operations and the like.

Type 4X - Watertight and Corrosion resistant

Similar to Type 4, but suitable for service in an environment which is likely to cause corrosion, such as exposure to harsh cleaning agents or salt water.

Type 5 - Dust-Tight

A dust-tight enclosure is so constructed as to exclude dust.

Type 6 - Submersible

A submersible enclosure is intended to permit the enclosed apparatus to operate successfully when submerged in water under specified conditions of pressure and time.

Type 7 (A, B, C, or D)* Hazardous Locations, Class I-Air Break

These enclosures are designed to meet the application requirements of the National Electrical Code for Class I Hazardous Locations which may be in effect from time to time. In this type of equipment, the circuit interruption occurs in air. *The letter or letters following the type number indicates the particular group or groups of hazardous locations (as defined in the National Electrical Code) for which the enclosure is designed. The type designation is incomplete without a suffix letter or letters.

Type 8 (A, B, C, or D)* Hazardous Locations, Class I-Oil Immersed

These enclosures are designed to meet the application requirements of the National Electrical Code for Class I Hazardous Locations which may be in effect from time to time. The apparatus is immersed in oil. *The letter or letters following the type number indicates the particular group or groups of hazardous locations (as defined in the National Electrical code) for which the enclosure is designed. The type designation is incomplete without a suffix letter or letters.

Type 9 (E, F, or G)* Hazardous Locations, Class II

These enclosures are designed to meet the application requirements of the National Electrical Code for Class II Hazardous Locations which may be in effect from time to time. *The letter or letters following the type number indicates the particular group or groups of hazardous locations (as define in the National Electrical Code) for which the enclosure is designed. The designation is incomplete without a suffix letter or letters.

Type 10 - Bureau of Mines-Explosion-proof

This enclosure is designed to meet the explosion proof requirements of the U.S. Bureau of Mines which may be in effect from time to time. It is suitable for use in gassy coal mines.

Type 11 - Acid- or Fume-Resistant-Oil Immersed

This enclosure provides for the immersion of the apparatus in oil such that it is suitable for application where the equipment is subject to acid or other corrosive fumes.

Type 12 - Industrial Use

An industrial use enclosure is designed for use in those industries where it is desired to exclude such materials as dust, lint, fibers and flyings, oil seepage or coolant seepage.

Type 13 - Dust-Proof

A dust-proof enclosure is intended primarily to prevent accidental contact with the enclosed apparatus and, in addition, is so constructed that dust which may enter will not interfere with the operation of the apparatus. The construction of the enclosure can be defined only in relation to the apparatus and to the amount and kind of dust present.


Definitions

Acid-resistant

Acid-resistant means so constructed that it will not be injured readily by exposure to acid fumes.

Dustproof

Dustproof means so constructed or protected that dust will not interfere with its successful operation.

Dust-tight

Dust-tight means so constructed that dust will not enter the enclosing case.

Fume-resistant

Fume-resistant means so constructed that it will not be injured readily by exposure to the specified fumes.

Moisture-resistant

Moisture-resistant means so constructed or treated that it will not be injured readily by exposure to a moist atmosphere.

Oil-tight

Oil-tight means so constructed that oil will not enter the enclosing case.

Rain-tight

Rain-tight means so constructed or protected that exposure to a beating rain will not result in the entrance of water.

Sleetproof

Sleetproof means so constructed or protected that the accumulation of sleet will not interfere with its successful operation.

Splashproof

Splashproof means so constructed and protected that external splashing will not interfere with its successful operation.

Submersible

Submersible means so constructed that it will operate successfully when submerged in water under specified conditions of pressure and time.

Watertight

Water-tight means provided with an enclosing case which will exclude water applied in the form of a hose stream under specified conditions.

Weatherproof (Outside Exposure)

Weatherproof means so constructed or protected that exposure to the weather will not interfere with its successful operation.


Thanks to The Graybar Electric Company for the information upon which this article is based.

Author: Roy A. Anderson,
President The Roy Anderson Company, Inc. (TRACo, Inc.)

1049 Red Bird Rd.

Loveland,

Ohio 45140

Phone: 513-683-7657

Fax: 513-683-7657

E-Mail address: isis@iac.net


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