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All NEC references by Electrical Helper are interpretations of the NEC by the Electrical Helper staff and are not NEC statements. The official position of the NEC requires that the NEC be referred to in its entirety.

Table 110.20  Enclosure Selection 
For Outdoor Use 
Enclosure-Type Number
Provides a Degree of Protection Against the Following Environmental Conditions 3 3R 3S 3X 3RX 3SX 4 4X 6 6P
Incidental contact with the enclosed equipment X X X X X X X X X X
Rain, snow, and sleet X X X X X X X X X X
Sleet* — — X — — X — — — —
Windblown dust X — X X — X X X X X
Hosedown — — — — — — X X X X
Corrosive agents — — — X X X — X — X
Temporary submersion — — — — — — — — X X
Prolonged submersion — — — — — — — — — X
For Indoor Use
Enclosure-Type Number
Provides a Degree of Protection Against the Following Environmental Conditions 1 2 4 4X 5 6 6P 12 12K 13
Incidental contact with the enclosed equipment X X X X X X X X X X
Falling dirt X X X X X X X X X X
Falling liquids and light splashing — X X X X X X X X X
Circulating dust, lint, fibers, and flyings — — X X — X X X X X
Settling airborne dust, lint, fibers, and flyings — — X X X X X X X X
Hosedown and splashing water — — X X — X X — — —
Oil and coolant seepage — — — — — — — X X X
Oil or coolant spraying and splashing — — — — — — — — — X
Corrosive agents — — — X — — X — — —
Temporary submersion — — — — — X X — — —
Prolonged submersion — — — — — — X — — —
*Mechanism shall be operable when ice covered.
FPN: The term raintight is typically used in conjunction with Enclosure Types 3, 3S, 3SX, 3X, 4, 4X, 6, and 6P. The term rainproof is typically used in conjunction with Enclosure Types 3R, and 3RX. The term watertight is typically used in conjunction with Enclosure Types 4, 4X, 6, 6P. The term driptight is typically used in conjunction with Enclosure Types 2, 5, 12, 12K, and 13. The term dusttight is typically used in conjunction with Enclosure Types 3, 3S, 3SX, 3X, 5, 12, 12K, and 13.