NEMA Enclosure Ratings Guide
Standard NEMA (National Electrical Manufacturers’ Association) Enclosure Ratings Guide
Comparison of Indoor Rated Enclosures
| Provides a degree of protection against the following conditions: |
Type of Enclosure | ||||
|---|---|---|---|---|---|
| 1 | 4 | 4X | 7 | 12 | |
| Incidental contact with enclosed equipment | X | X | X | X | X |
| Falling dirt | X | X | X | X | X |
| Falling liquids and light splashing | X | X | X | X | |
| Dust, lint, and fibers | X | X | X | X | |
| Hosedown (hose directed water) | X | X | X | ||
| Oil and coolant seepage | X | X | |||
| Corrosive agents | X | X | |||
| Potentially explosive gas-air mixture | X | ||||
| Windblown dust | X | X | |||
Comparison of Outdoor Rated Enclosures
| Provides a degree of protection against the following conditions: |
Type of Enclosure | |||
|---|---|---|---|---|
| 3 | 3R | 4 | 4X | |
| Incidental contact with enclosed equipment | X | X | X | X |
| Rain, snow and sleet | X | X | X | X |
| Windblown dust | X | X | X | |
| Hosedown (hose-directed water) | X | X | ||
| Corrosive agents | X | |||
- Type 1 – General Purpose Enclosures are intended for indoor use primarily to provide a degree of protection against contact with the enclosed equipment in locations where unusual service conditions do not exist.
- Type 3 – Weather Resistant & Windblown Dust Resistant Enclosures are intended for outdoor use primarily to provide a degree of protection against windblown dust, rain, and sleet; and to be undamaged by the formation of ice on the enclosure.
- Type 3R – Weather Resistant Enclosures are intended for outdoor use primarily to provide a degree of protection against falling rain and sleet, and to be undamaged by the formation of ice on the enclosure.
- Type 4 – Moisture & Windblown Dust Resistant Enclosures are intended for indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose-directed water; and to be undamaged by the formation of ice on the enclosure.
- Type 4X – Moisture & Corrosion Resistant Enclosures are intended for indoor or outdoor use primarily to provide a degree of protection against corrosion, windblown dust and rain, splashing water, and hose- directed water; and to be undamaged by the formation of ice on the enclosure.
- Type 7 – Explosion Resistant Enclosures are capable of withstanding the pressures resulting from an internal explosion of specified gas, and containing such an explosion sufficiently that an explosive gas-air mixture existing in the atmosphere surrounding the enclosure will not be ignited.
- Type 12 – Resistant to Dirt & Dripping Non-Corrosive Liquids Enclosures are intended for indoor use primarily to provide a degree of protection against dust, falling dirt, and dripping non-corrosive liquids.
