March 30-31, 2017
Ohio Fuel Cell Symposium 2017
Elyria, Ohio

NEMA and IP Comparisons
Understanding IP and NEMA Ratings

The protection of enclosures against ingress of dirt or against the ingress of water is defined in IEC529 (BSEN60529:1991). Conversely, an enclosure which protects equipment against ingress of particles will also protect a person from potential hazards within that enclosure, and this degree of protection is also defined as a standard.

The degrees of protection are most commonly expressed as "IP" followed by two numbers, e.g. IP65, where the numbers define the degree of protection. The first digit (Foreign Bodies Protection)shows the extent to which the equipment is protected against particles, or to which persons are protected from enclosed hazards. The second digit (Water Protection) indicates the extent of protection against water. The wording in the table is not exactly as used in the standards document, but the dimensions are accurate.

The first digit in the rating is the protection against contact and foreign bodies. The second digit in the rating is the water protection factor. The third digit in the impact protection factor It is normally displayed in the format below.

IP Code, (International Protection) an international standard rating for the protection of electrical equipment against accidental contact and the ingress of dust and water.

IP s l (i)
IP= International Protection s = solids, l=liquids and i= impact (optional)

First Index - Foreign Bodies Protection, Solids
Index Protection against Human/Tool Contact Protection against solid objects (foreign bodies)
0 No special protection
1 Back of hand, Fist Large foreign bodies, diam. >50 mm
2 Finger Medium-sized foreign bodies, diam. >12
3 Tools and wires etc with a thickness >2.5 mm Small foreign bodies, diam. >2.5 mm
4 Tools and wires etc with a thickness >1 mm Granular foreign bodies, diam. >1 mm
5 Complete protection, (limited ingress permitted) Dust protected; dust deposits are permitted, but their volume must not affect the function of the unit.
6 Complete protection Dust-proof

Second Index - Water Protection, Liquids
Index Protection against water Protection from condition
0 No special protection
1 Water dripping/falling vertically Condensation/Light rain
2 Water sprayed at an angle (up to 15° degrees from the vertical) Light rain with wind
3 Spray water (any direction up to 60° degrees from the vertical) Heavy rainstorm
4 Spray water from all directions, (limited ingress permitted) Splashing
5 Low pressure water jets from all directions, (limited ingress permitted) Hose down, residential
6 High pressure jets from all directions, (limited ingress permitted) Hose down, commercial. eg. Ship decks
7 Temporary immersion, 15 cm to 1 m Immersion in tank
8 Permanent Immersion, under pressure For use on Titanic recovery vehicle

Third Index - Impact Protection, Impact
Index Protection against impact Equivalent mass impact
0 No special protection
1 Protected against 0.225 J impact eg. 150 g weight falling from 15 cm height
2 Protected against 0.375 J impact eg. 250 g weight falling from 15 cm height
3 Protected against 0.5 J impact eg. 250 g weight falling from 20 cm height
4 Protected against 2.0 J impact eg. 500 g weight falling from 40 cm height
5 Protected against 6.0 J impact eg. 0.61183 kg weight falling from 1 m height
6 Protected against 20.0 J impact eg. 2.0394 kg weight falling from 1 m height

Comparing NEMA enclosures and IEC Equivalents.
IEC equivelants listed here are general approximations. For example, the PW12 rating is less stringent than the IP69K rating. It is the responsibility of the user to verify the enclosure rating necessary for the given application.

Enclosure type








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