Enclosures

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Enclosures are required to house disconnects, motor starters, and other motor controls. The enclosures are available in a variety of designs that will protect the devices inside from all types of environmental conditions. Figure 1 shows a list of typical enclosure types as classified by the National Electrical Manufacturers Association (NEMA), and Figure 2 shows examples of each type of enclosure.

Type 1 enclosures are designed for general-purpose applications in indoor locations. That is, the enclosure should not be exposed to extreme conditions, such as excessive moisture. Type 2 enclosure is rated for drip-proof conditions that exist indoors. That is, some moisture may come in contact with the enclosure, but it's not approved where equipment must be washed down or steam cleaned daily.

Type Enclosure
1) General put pose, indoor
2) Drip-proof, indoor
3) Dust, tight. Rain-tight. sleet, tight, outdoor
3R Rainproof, sleet resistant outdoor
3S Dust, tight. Rain tight. Sleet proof, outdoor
4 Watertight, dust-tight. Sleet resistant, indoor
4X Watertight. dust, tight, corrosion resistant, in door/outdoor
5 Dust-tight, -indoor
6 Submersible watertight dust-tight sleet
resistant, indoor/outdoor
7 Class I, group A, B, C, or D hazardous locations air, break, indoor
8 Class I, group A, B, C , or D hazardous locations, oil-immersed, indoor
9 Class II. group E F or C hazardous locations a -break, indoor
10) Bureau of Mines
11) Corrosion-resistant & drip-proof, oil immersed, indoor 
12) Industrial use, dust, tight & drip-tight, indoor Oil tight & dust-tight, indoor
Above
: Fig. 1: List of enclosure types provided by the National Electric Manufacturers Association (NEMA).

NEMA Type 4X
Non-Metallic.
Corrosion-Resistant
Fiberglass Reinforced
Polyester
Type 4X enclosures are intended for in door or outdoor use primarily to provide a degree of protection against corrosion, windblown dust & rain, water, & hose-directed water They are designed to meet the hose-down, dust, icings, & corrosion-resistance design tests They are not intended to provide protection against conditions such as internal condensation or internal icing Enclosure is fiberglass reinforced polyester with a synthetic rubber gasket between cover & bass ideal for such industries as chemical plants & paper mrtts
NEMA Type SP
Type EP enclosures are intended for in door or outdoor use primarily to provide a degree of protection against the entry of water during prolonged submersion at a limited depth They are designed to meet air pressure, icing , end corrosion-resistance design tests They are not intended to provide protection against conditions such as internal con destination or internal icing
NEMA Type 7
For Hazardous
Gas Locations
Bolted Enclosure
Type 7 enclosures sin tor indoor use in locations ctassitr as class t, Groups C or 0. as dstrned in the National Electrical code Type 7 enclosures are designed to be capable of withstanding the pressures resulting from an internal explosion of specified gases. & contain such an c piosion suftrcientty thet sn espiosrve gas air misture enisting in the atmosphere surrounding the enclosure writ not be ig rsted Enclosed heat generating devices are designed not to cause esfernat sur tacos to reach temperatures capable of igniting esplosine gas-air mrntures in the surrounding atmosphere Enclosures we designed to meet eeplosion, hydrostatic, & temperature design tests. Finish is a special corrosion-resistant, gray enamel
NEMA Type 9
For Hazardous
Dust Locations
Type 9 enclosures are mtendnd for indoor use in locations ciassitred ss class It. Groupe E, F or C, as detined in the Na tional Electrical Code Type 9 enclosures are designed to be capable ot preventing the entrance of dust Enclosed heat gen erating devices are designed not to cause enternal surtaces to reach temper atures capable of igniting or discoloring dust on the enclosure or igniting dust-sri mistures in the surrounding atmosphere. Enclosures are designed to meet dust penetratron & temperature design tests, & aging of gaskets The outside frmah is 5 special corrosion-resistant gray enamel
NEMA Type 12
Type t2 enclosures are intended for in door use primarily to provide a degree of protection against dust, tailing dirt, & dipping non-corrosion liquids They are designed to meet dripS dust, & rust- resistance tests They are not intended to provide protection against conditions such as rnfernat condensation
NEMA Type 13
Type 13 esclosuien are intended f or in door use primarily to provide a degree of protection against dust spraying ot water, oil, & noncoiroave coofant They are designed fo meet oil eactuston & rust-resistance design tests They ate not intended to provide protection against conditions such as internal condensation.
r
Type t ersctesures are attended ton indoor use prirtsarily to provide a degree of pro lection against contact with the enclosed eqi,vpment in locations where unusual service conditions don't ernst The en- closures ate designed to meet the rod entry end rust resistance design lest Encosuve if sheet steel treated to resist corrosion
Ftustt nsourtted enclosures for antaaatiort in rmactsrne fravties & plaster waft these enclosures are for similar appfica’ hens & are designed to meet the same tests as MMA type 1 surf ace rnountasg PIEMA type 3
Type 3 enclosures are intended for out door use primarily to preside a degree of protectet against winShOwn dust, rain. steel, & eeternal ice formation t
are designed 10 erect rantS, eslerrsat ic vrgfl dust artd rust-resistance det tests They are net intended tO preside protection agarnet conditions such aa in ternai cersderrsalrern or asteersal tasg
Type 3Ff enclosures are intended Per out door use pnrtsanly to provide a degree of pretechen againsf laeetg rain, steel & eaternal ice formation They are designed to meet rod entry. rainS eatemnai ic ingt & rust-resistance design tests They are not attended t provide protection against conditions such as dust at serrsai condensation or internal icing
Type 4 enclosures are intended for indoor or outdoor use primarily to provide a de ee of protection against erevotslown dust & last splashing wafer & hoes- directed eater They are designed to meet hosedoert dust eoterriai icingS & ruaf -resistance design tests Traey are not intended to provide protection against cor*tione such at internal con densaf ion or internal Icing Enclosures are nsade 01 heavy gauge etaeviess steel, cast airalneturni or heavy gauge sheet steei depending çn the type 01 urat & size Cover has a synthetic rubber gasket
NEMA Type 3$. 7 Unftoctt Enclosure
Per Nazardove Locat
This enclosure is cast front topper-f re& (less than 0 t 5 aluminium & the entire enclosure (including interior & ttange areas) it bronze chromaled. The interior surfaces are also primed with a special epovy primer & finished with an ala phattc urethane paint for estra corrosion resistance The V-Band permits easy removal of the cover for inspection arid for making field modifications This enclosure meets the same tests aa separate NEMA type 3Ff, & NEMA Type 7 & 9 enclosures For NEMA Type 3Ff application, it's necessary that a drain be added
PtMA Type I nn , 
NEMA Type 1
C Mounting
NEMA Type 3$
NEMA Type 4
Above
: Fig. 2: Examples of NEMA-rated enclosures.

Type 3 enclosures are designed for dust-tight, rain-tight, and sleet-tight conditions that exist outdoors, and type 3R rain-proof, sleet-resistant, and type 3S enclosures are designed for dust-tight, raintight, and sleet-proof conditions. These enclosures are intended for protection against falling rain, sleet, or dust. They are not NEMA enclosures for starters intended to prevent condensation from forming on the inside of the enclosure or on internal components in the enclosure.

If the application is located where windblown water or sleet may be encountered, a type 4 enclosure should be used. The type 4 and 4X enclosures are designed to protect against windblown dust, rain, or water from direct-hose-down conditions. This enclosure is specified by NEMA for water-tight, dust-tight, sleet-resistant indoor and outdoor applications. The 4X enclosure also provides protection in environments where corrosion resistance is required. The covers of these enclosures have protective gaskets that provide a barrier against these conditions. All hardware for conduits must match the same requirements to maintain the integrity of the design throughout the installation.

Type 5 enclosures are designed for dust-tight applications located indoors. This type of enclosure is designed to protect the switch and contacts from a buildup of dust that may prevent proper operation of the switches and starters that are en closed.

Type 6 enclosures are designed to provide submersible, water-tight, dust- tight, sleet-resistant indoor and outdoor applications. The submersible water-tight specification allows the switch to be fully submersed in water to a limited depth and maintain water-tight integrity. This type of enclosure also depends on gaskets to maintain the water-tight condition. As with other enclosures, conduits and connectors must meet the same NEMA standard so that the entire installation maintains the stated protection.

Type 7 enclosures provide class I protection for group A, B, C, or D hazardous locations, with air-break protection for indoor locations. These enclosures are de signed to prevent dangerous gases from penetrating the enclosure and coming into contact with the open parts of switches or other controls. This provides protection in explosive atmospheres. Class I locations are hazardous because flammable gases or vapors may be present in sufficient quantities to cause explosions. Type 8 enclosures provide class 1, group A, B, C, or D hazardous locations, oil immersed for indoor applications. This type of enclosure is very similar to the type 7 enclosure except that it will provide protection against oil immersion instead of air break. This allows the enclosure to be used where oil and machine coolants are used extensively.

Type 9 enclosures provide protection against class II, group E, F, or G hazardous locations and air break for indoor applications. Class II locations are hazardous because of the presence of combustible dust in quantities sufficient to explode or ignite.

Type 10 enclosures are rated for all applications within mines. This type of enclosure must be able to protect switch gear against explosive conditions. Type 11 enclosures provide corrosion resistance and drip-proof, oil-immersion protection for indoor applications. This type of enclosure is used where the vapors and fumes may be corrosive to switch gear or other motor controls that are mounted inside. The exterior of the enclosure is also resistant to corrosion from these fumes. This type of enclosure is also used for applications where machining operations are per formed.

Type 12 enclosures are intended for indoor applications to provide protection against dust, falling dirt, and dripping non-corrosive materials. They are not intended for use against direct spraying of these materials. The last classification of enclosures is type 13.

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