Electrical equipments used in process areas are protected against the ingress of foreign particles/water. The classification of ingress protection is given in table.
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 shows the extent to which the equipment is protected against particles, or to which persons are protected from enclosed hazards. The second digit 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.
Protection of machine against solid particle
2nd charact no.
Protection of machine against penetrating of water
Particles > 50mm
Vertically dripping water
Water angled at 75-90deg
Effect of immersion
IP Degree of Protection according to EN/IEC 60529
Correlations between IP (IEC) and NEMA 250 standards
- IP10 -> NEMA 1
- IP11 -> NEMA 2
- IP54 -> NEMA 3 R
- IP52 -> NEMA 5-12-12 K
- IP54 -> NEMA 3-3 S
- IP56 -> NEMA 4-4 X
- IP67 -> NEMA 6-6 P