IP Protection Classes
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.
| First Digit |
Protection against Human Contact |
Protection against Foreign Bodies |
| 0 | No special protection | No special protection |
| 1 | With back of hand | Large foreign bodies, diam. >50mm |
| 2 | With a finger | Medium-sized foreign bodies, diam. >12.5mm |
| 3 | With tools and wires etc with a thickness >2.5mm | Small foreign bodies, diam. >12.5mm |
| 4 | With tools and wires etc with a thickness >1mm | Granular foreign bodies, diam. >1mm |
| 5 | Complete protection | Dust protected; dust depostites are permitted, but their volume must not affect the function of the unit |
| 6 | Complete protection | Dust-proof |
| Second Digit |
Protecton against Water Ingress |
| 0 | No special protection |
| 1 | Water dripping vertically |
| 2 | Water dripping at an angle (up to 15 degress from the vertical) |
| 3 | Spray water (any direction up to 60 degress from the vertical) |
| 4 | Spray water from all directions |
| 5 | Water jets from a nozzle in all directions |
| 6 | High pressure jets |
| 7 | Temporary immersion |
| 8 | Permanent immersion |
