IP & NEMA Ratings Explained

IP ratings cover protection against the ingress of water and solid objects whereas NEMA includes protection standards against corrosion and atmospheric gasses. The information below will cover both ratings and how they differ.

• IP stands for Ingress Protection

• The rating’s first digit, i.e. the “5” in IP56, relates to the ingress protection against dust (5 means dust protected, as in the table below) The second digit relates to the ingress protection against water (6 means protected against heavy water jets; see the table below)

IP First Digit – Protection Against Solids
LevelProtection Against Human/Tool ContactProtection Against Solid Objects (Foreign Bodies)
0No special protection-
1Back of hand, FistLarge foreign bodies, >50mm diameter
2FingerMedium-sized foreign bodies, >12 diameter
3Tools, thick wires, etc.Small foreign bodies, >2.5mm diameter
4Thin wires, screws, etc.Granular foreign bodies, >1mm diameter
5Complete protection, (limited ingress permitted)Dust protected; dust deposits are permitted, but their volume must not affect the function of the unit.
6Complete protectionDust-proof
IP Second Digit – Protection Against Liquids
LevelProtection Against WaterProtection From Condition
0No special protection
1Water dripping/falling verticallyCondensation/Light rain
2Water sprayed at an angle (up to 15º from vertical)Light rain with wind
3Spray water (any direction up to 60º from vertical)Heavy rainstorm
4Splashing/spray water from all directions
(limited ingress permitted)
Splashing
5Low pressure water jets from all directions
(limited ingress permitted
Hose down, residential
6High pressure water jets from all directions
(limited ingress permitted
Hose down, commercial
7Submersible (temporary) 15 cm to 1MImmersion in tank
8Permanent Submersion, under pressure over 1 M depthFor use underwater
IP Rating vs NEMA Ratings

NEMA defines standards for various grades of enclosures. Each is rated to protect against designated environmental conditions such as water, dust, etc. The following is a description of the NEMA ratings, and their approximate IP-rating equivalents.

NEMA RatingDefinitionApproximate IP
Equivalent
1General-purpose. Protects against dust, light, and indirect splashing but is not dust-tight; primarily prevents contact with live parts; used indoors and under normal atmospheric conditions.IP10
2Drip-tight. Similar to Type 1 but with addition of drip shields; used where condensation may be severe (as in cooling and laundry rooms).IP11
3 and 3SWeather-resistant. Protects against weather hazards such as rain and sleet; used outdoors on ship docks, in construction work, and in tunnels and subways.IP54
3RIntended for outdoor use. Provides a degree of protection against falling rain and ice formation. Meets rod entry, rain, external icing, and rust-resistance design tests.IP14
4 and 4XWatertight (weatherproof). Must exclude at least 65 GPM of water from 1-in. nozzle delivered from a distance not less than 10 ft. for 5 min. Used outdoors on ship docks, in dairies, and in breweries.IP56
5Dust-tight Provided with gaskets or equivalent to exclude dust; used in steel mills and cement plants.IP52
6 and 6PSubmersible. Design depends on specified conditions of pressure and time; submersible in water or oil; used in quarries, mines and manholes. IP67
7Hazardous. For indoor use in Class I, Groups A, B, C, and D environments as defined in the NEC.-
8Hazardous. For indoor and outdoor use in locations classified at Class I, Groups A, B, C, and D as defined in the NEC.-
9Hazardous. For indoor and outdoor use in locations classified as Class II, Groups E, F, or G as defined in the NEC.-
10MSHA. Meets the requirements of the Mine Safety and Health Administration, 30 CFR Part 18 (1978).-
11General-purpose. Protects against the corrosive effects of liquids and gases. Meets drip and corrosion-resistance tests. -
12 and 12KGeneral-purpose. Intended for outdoor use, provides some protection against dust, falling dirt, and dripping noncorrosive liquids. Meets drip, dust, and rust resistance tests.IP52
13General-purpose. Primarily used to provide protection against dust, spraying of water and noncorrosive coolants. Meets oil exclusion and rust resistance design tests.IP54