NEMA Enclosure Ratings

 What do the NEma enclosure ratings or types mean?

NEMA enclosure ratings specify what a NEMA enclosure must do. The National Electrical Manufacturers Association (NEMA) is a US Manufacturers Organization which promotes standardized product specifications for electrical apparatus. NEMA does not test products, it establishes the performance criteria for enclosures intended for different environments.

NEMA specifies what an enclosure must do, not how to fabricate it. NEMA performance criteria and test processes are used by Underwriters Laboratories (UL) and the Canadian Standards Association (CSA) as guidelines for investigation and listing of electrical enclosures. The tested enclosures are then authorized to carry a label by UL or CSA to prove it has passed the required tests and meets the applicable UL and CSA standard.

 NEMA 1 Enclosures

General purpose enclosures. They protect against dust, light and indirect splashing but is not dust-tight; primarily prevents contact with live parts. It is used indoors and under normal atmospheric conditions.

 NEMA 2 Enclosures

Drip-tight. Similar to Type 1 but they include drip shields. They are used where condensation may be severe (as in cooling and laundry rooms).

 NEMA 3, 3s, 3x Enclosures

Weather-resistant enclosures that protect against weather hazards such as rain and sleet; used outdoors on ship docks, in construction work environments and in tunnels and subways. NEMA 3X includes protection against corrosion.

NEMA 3r Enclosures

Intended for outdoor use. NEMA 3R enclosures provide a degree of protection against falling rain and ice formation. Meet rod entry, rain, external icing and rust-resistance design tests.

 NEMA 4/4x Enclosures

Watertight (weatherproof). Must exclude at least 65 GPM of water from 1-in. nozzle delivered from a distance not less than 10ft for 5 minutes. These type of enclosures are typically used outdoorson ship docks, in dairies, and in breweries. The 4X NEMA enclosures have corrission resistance.

 NEMA 5 Enclosures

NEMA 5 enclosures are dust tight. They are provided with gaskets or equivalent in order to exclude dust. They are typically used in steel mills and cement plants.

 NEMA 6/6p Enclosures

These types of enclosures are submersible. Their design depends on specified conditions or pressure and time. They can be submerged in water or oil. They are typically used in quarries, mines and manholes.

 NEMA 7 Enclosures

NEMA 7 enclosures are constructed for indoor use in hazardous (classified) locations classified as Class I, Division 1, Groups A, B, C, or D as defined in NFPA 70.

 NEMA 8 Enclosures

Enclosures constructed for either indoor or outdoor use in hazardous (classified) locations classified as Class I, Division 1, Groups A, B, C, and D as defined in NFPA 70.

 NEMA 9 Enclosures

Enclosures constructed for indoor use in hazardous (classified) locations classified as Class II, Division 1, Groups E, F, or G as defined in NFPA 70.

 NEMA 10 Enclosures

Enclosures constructed to meet the requirements of the Mine Safety and Health Administration, 30 CFR, Part 18.

 NEMA 11 Enclosures

NEMA 11 enclosures are general-purpose. They protect against the corrosive effects of liquids and gases. They meet drip and corrosion-resistance tests.

 NEMA 12/12k Enclosures

NEMA 12 enclosures are general-purpose and intended for indoor use only. They provide some protection against dust, falling dirt and dripping noncorrosive liquids. Meets drip, dust and rust resistance tests.

 NEMA 13 Enclosures

NEMA 13 enclosures are general-purpose. They are primarily used to provide protection against dust, spraying of water and noncorrosive coolants. They meet oil axclusion and rust resistance design tests.