NEMA/IP Number Definitions

NEMA-# Description
1 General Purpose (Indoor)
2 Water Drip Proof (Indoor)
3R Dust Tight, Rain Tight, and Ice Resistant (Outdoor)
4 Water Tight and Dust Tight (Indoor/Outdoor)
4X Water Tight, Dust Tight, and Corrosion Resistant (Indoor/Outdoor)
9 Indoor Hazardous Locations (Not Applicable to III Equipment)
12 Industrial Use - Dust Tight and Drip Tight (Indoor)
13 Oil Tight and Dust Tight (Indoor)
Example NEMA-4 is water tight and dust tight indoor and outdoor
First Digit - Airborne Contaminants Description
0 No Special Protection
1 Protected Against Solid Objects > 50 mm in Diameter
2 Protected Against Solid Objects > 12 mm in Diameter
3 Protected Against Solid Objects > 2.5 mm in Diameter
4 Protected Against Solid Objects > 1 mm in Diameter
5 Dust Protected
6 Dust Tight
Second DigitWater/Moisture Description
0 No Special Protection
1 Protected Against Dripping Water
2 Protected Against Dripping Water When Tilted Up to 15° C From Normal Position
3 Protected Against Spraying Water
4 Protected Against Splashing Water
5 Protected Against Water Jet Spray
6 Protected Against Heavy Jet Spray
7 Protected Against the Effects of Immersion
8 Protected Against Submersion
Example IP54 is dust protected, and protected against splashing water.