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DEFINITION
OF ELECTRICAL CLASSIFICATIONS
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Hazardous
Locations: |
Class I
Locations: |
Hazardous locations because flammable vapours may be
present in sufficient quantities to produce ignitable mixtures. |
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Class
I, Division 1: |
Locations in which ignitable concentrations of
flammable vapours can exist under normal operating conditions. |
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Class
I, Division 2: |
Locations in which flammable liquids are
used, but are normally confined within closed systems from
which they can escape only in the event of accidental breakdown. |
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Class
II Locations: |
Hazardous locations caused by combustible dust. |
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Class
III Locations: |
Hazardous locations caused by ignitable fibres. |
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Electrical Enclosures: |
NEMA 1: |
General Purpose: Enclosures for
indoor use to provide protection from incidental contact and protection against
falling dirt. |
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NEMA 2: |
Drip Tight: Enclosures for indoor
use to provide protection from falling water and dirt. |
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NEMA 3: |
Water Resistant: Enclosures for
outdoor use to provide protection from wind blown dust and rain. Undamaged by
ice formation on the enclosure. |
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NEMA 3R: |
Rain Tight: Enclosures for
outdoor use to provide protection from wind blown rain. Undamaged by ice
formation on the enclosure. |
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NEMA 4: |
Water Tight: Enclosures for
outdoor use to provide protection from wind blown dust and rain, splashing
water, and hose directed water. Undamaged by ice formation on the enclosure. |
| NEMA 4X: |
Corrosion Resistant: Enclosures
for outdoor use to provide protection from corrosion, wind blown dust and rain,
splashing water, and hose directed water. Undamaged by ice formation on the
enclosure. |
| NEMA 5: |
Dust Tight: Enclosures for indoor
use to provide protection from falling dust. |
| NEMA 6: |
Submersible: Enclosures for
outdoor use to provide protection against submersion in water. |
| NEMA 7: |
Hazardous Locations: Enclosures
for class I hazardous locations (presence of flammable vapours). Circuit
interruption occurs in air. |
| NEMA 8: |
Hazardous Locations: Enclosures for class II, oil immersed, groups A, B, C, and
D hazardous locations (explosive atmosphere). Circuit interruption occurs in
oil. |
| NEMA 9: |
Hazardous Locations:
Enclosures for class II, groups E, F, and G hazardous locations (presence of
combustible dusts) |
| NEMA 10: |
Mines:
Enclosures for hazardous locations (such as coal mines). |
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NEMA
11: |
Acid Mists: Enclosures for use in corrosive atmospheres. |
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Electrical Requirements for Solvent Extraction Plants: |
SX Plants with Combustible Liquids: |
Electrical wiring and components in solvent
extraction plants with combustible liquids (class II or class IIIA combustible
liquids) should be suitable for general purpose locations with NEMA 4 or NEMA 4X
enclosures. |
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SX Plants with Flammable Liquids: |
Electrical wiring and components in solvent extraction plants with flammable
liquids (1A, 1B, or 1C flammable liquids) should be suitable for class I,
division 2 hazardous locations with NEMA 7 enclosures. |
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 For more details regarding classes of combustible and flammable liquids:
Combustible
/ Flammable Liquids
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