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Section II – Introduction
E. Reference Standards. (Refer to Table 9.)
Non-Hazardous Locations
Type 1 enclosures are intended for indoor use primarily to provide a
degree of protection against contact with the enclosed equipment.
Type 3 enclosures are intended for outdoor use primarily to provide a
degree of protection against windblown dust, rain, sleet, and external ice
formation.
Type 4 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.
Type 4X 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.
Type 6 enclosures are intended for indoor and outdoor use primarily to
provide a degree of protection against the entry of water during
occasional temporary submersion at a limited depth.
Type 13 enclosures are intended for indoor use primarily to provide a
degree of protection against dust, spraying of water, oil, and non-
corrosive coolant.
Hazardous Locations
Type 7 enclosures are for use indoors in locations classified as Class I,
Groups B, C, or D as defined in the National Electrical Code.
• Group B – Atmospheres containing hydrogen manufactured gas.
• Group C – Atmospheres containing diethyl ether, ethylene, or
cyclopropane.
• Group D – Atmospheres containing gasoline, hexane, butane,
naphtha, propane, acetone, toluene, or isoprene.