The degrees of protection are most commonly expressed as "IP" followed by two numbers, e.g. IP65, where the numbers define the degree of protection. The first digit (Foreign Bodies Protection) shows the extent to which the equipment is protected against particles, or to which persons are protected from enclosed hazards. The second digit (Water Protection) indicates the extent of protection against water. The wording in the table is not exactly as used in the standards document, but the dimensions are accurate.
The first digit in the rating is the protection against contact and foreign bodies. The second digit in the rating is the water protection factor. The third digit in the impact protection factor. It is normally displayed in the format below.
IP s l (i)
Where, s = solids, l = liquids and i = impact (optional)
NEMA Ratings
There are many NEMA ratings available for enclosures. Below, is an brief explanation of each NEMA rating.
NEMA 1 General Purpose - Indoors
Type 1 enclosures are intended for general purpose indoor use primarily to provide a degree of protection against contact with the enclosed equipment or locations where unusual service conditions do not exist.
NEMA 2 Drip Proof - Indoors
Type 2 enclosures are intended for general purpose indoor use primarily to provide a degree of protection against limited amounts of falling water and dirt.
NEMA 3 Dust Tight, Rain Tight, & Ice/Sleet resistant - Indoors/Outdoors
Type 3 enclosures are intended for general purpose 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.
NEMA 3R Rain Proof & Ice/Sleet Proof - Indoors/Outdoors
Type 3R enclosures are intended for general purpose outdoor use primarily to provide a degree of protection against falling rain; and to be undamaged by the formation of ice on the enclosure.
NEMA 3S Dust Tight, Rain Tight, & Ice/Sleet Proof - Outdoors
Type 3S enclosures are intended for general purpose outdoor use primarily to provide a degree of protection against sleet; and to be undamaged by the formation of ice on the enclosure.
NEMA 4 Water Tight & Dust Tight - Indoors/Outdoors
Type 4 enclosures are intended for general purpose 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.
NEMA 4x Water Tight, Dust Tight, & Corrosion Resistant - Indoors/Outdoors
Type 4X enclosures are intended for general purpose indoor and 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.
NEMA 5 Superseded by NEMA 12 for Control Apparatus
Type 5 see NEMA 12
NEMA 6 Submersible, Water Tight, Dust Tight, & Ice/Sleet Resistant - Indoors/Outdoors
Type 6 enclosures are intended for general purpose indoor or outdoor use primarily to provide a degree of protection against the entry of water during temporary submersion at a limited depth; and to be undamaged by the formation of ice on the enclosure.
NEMA 7 Underwriters Lab Class 1-Groups C&D -Explosion Proof - Indoors
Type 7 enclosures are for indoor use in locations classified as Class I, Groups A, B, C, or D, as defined in the National Electrical Code.
Type 7 enclosures shall be capable of withstanding the pressures resulting from an internal explosion of specified gases, and contain such an explosion sufficiently that an explosive gas-air mixture existing in the atmosphere surrounding the enclosure will not be ignited. Enclosed heat generating devices shall not cause external surfaces to reach temperatures capable of igniting explosive gas-air mixtures in the surrounding atmosphere. Enclosures shall meet explosion, hydro-static, and temperature design tests.
NEMA 8 Underwriters Lab Class 1-Groups C&D -Explosion Proof - Indoors
Type 8 is same as NEMA 7, except the unit is oil-immersed
NEMA 9 Underwriters' Lab Class II - Groups E,F,G - Indoors
Type 9 enclosures are intended for special purpose indoor use in locations classified as hazardous (Class II, Groups E, F, or G, as defined in the National Electrical Code).
Type 9 enclosures shall be capable of preventing the entrance of dust. Enclosed heat generating devices shall not cause external surfaces to reach temperatures capable of igniting or discoloring dust on the enclosure or igniting dust-air mixtures in the surrounding atmosphere. Enclosures shall meet dust penetration and temperature design tests, and aging of gaskets (if used).
NEMA 10 Bureau of Mines
NEMA 11 Corrosion Resistant & Drip Proof - Oil Immersed - indoors
NEMA 12 Industrial Use - Dust Tight & Drip Tight - Indoors
Type 12 enclosures are intended for industrial indoor use primarily to provide a degree of protection against dust, falling dirt, and dripping noncorrosive liquids.
NEMA 13 Oil Tight & Dust Tight - Indoors
Type 13 enclosures are intended for industrial indoor use primarily to provide a degree of protection against dust, spraying of water, oil, and noncorrosive coolant.
Comparing NEMA and IP enclosure ratings.
This comparison is only approximate, and it is the responsibility of the user to verify the enclosure rating necessary for the given application.
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