Nema Enclosure Standards
Reference data and engineering information about nema enclosure standards for standard organizations applications.
nemaenclosurestandards
Overview
Engineering reference data for Nema Enclosure Standards in standard organizations.
Key Formulas
ISO Standard
Quality management systems.
ASTM Standard
Standard test methods for tension testing.
ANSI Standard
Pipe flanges and flanged fittings.
Variables
| Symbol | Description | Unit |
|---|---|---|
| International Organization for Standardization | — | |
| American Society for Testing and Materials | — | |
| American National Standards Institute | — |
NEMA Enclosure Types Summary
| Enclosure Type | Description | Typical Environment |
|---|---|---|
| Drip-Proof | Ventilation openings prevent drops of liquid from falling into motor within a 15° angle from vertical. | Indoors, reasonably dry, clean, and well-ventilated. Outdoors with protective cover. |
| TEAO (Totally Enclosed Air Over) | Dust-tight motors designed for use within the airflow of a shaft- or belt-driven fan. | Dirty or dusty environments where motor is in the fan's airstream. |
| TENV (Totally Enclosed Non-Ventilated) | Enclosed to prevent free air exchange (not airtight). Relies on convection cooling. | Exposed to dirt or dampness. Not for very moist or hazardous atmospheres. |
| TEFC (Totally Enclosed Fan Cooled) | Similar to TENV but includes an integral external fan for cooling. | General purpose. Suitable for dirty or damp locations. |
| Totally Enclosed, Hostile Environment | Designed for extreme moist and/or chemical environments. | Severe industrial or chemical environments. Not for hazardous locations. |
| Totally Enclosed Blower Cooled | Like TEFC but the external blower is on a power supply independent of motor speed. | Applications requiring full cooling at low motor speeds (e.g., with inverter drives). |
| Explosion-Proof | Enclosure constructed to contain an internal explosion and prevent ignition of surrounding atmosphere. | Areas with flammable gases, vapors, or combustible dusts (see Class/Group table). |
Explosion-Proof Motor Classifications
8 rows
Class | Group | Representative Atmospheres |
|---|---|---|
| I - Gases & Vapors | A | Acetylene |
| I - Gases & Vapors | B | Butadiene, ethylene oxide, hydrogen, propylene oxide |
| I - Gases & Vapors | C | Acetaldehyde, cyclopropane, diethyl ether, ethylene, isoprene |
| I - Gases & Vapors | D | Acetone, acrylonitrile, ammonia, benzene, butane, ethylene dichloride, gasoline, hexane, methane, methanol, naphtha, propane, propylene, styrene, toluene, vinyl acetate, vinyl chloride, xylene |
| II - Combustible Dusts | E | Aluminum, magnesium & other metal dusts with similar characteristics |
| II - Combustible Dusts | F | Carbon black, coke or coal dust |
| II - Combustible Dusts | G | Flour, starch or grain dust |
| III - Fibers & Flyings | G | Flour, starch or grain dust |
Source: NEMA MG1, IEC/NEC Standards