The IP degrees of protection (ingress protection) are defined by the International Electrotechnical Commission in its IEC 60529 standard. These protection classes classify the degrees of protection of unprocessed housings of electrical devices with a rated voltage of maximum 72.5 kV. (IEC standard 60529 as well as DIN EN 60529; VDE 0470-1:2000-09)

The abbreviation IP is followed by two digits. The first digit stands for protection against the penetration of solid bodies. The second digit describes the degree of protection against the ingress of water. The numbers have specific descriptions, which you can find in the tables.

First Digit: Solids

The first digit indicates the level of protection that the enclosure provides against access to hazardous parts (e.g., electrical conductors, moving parts) and the ingress of solid foreign objects.

LevelObject size protected againstEffective against
0Not protectedNo protection against contact and ingress of objects
1>50mmAny large surface of the body, such as the back of the hand, but no protection against deliberate contact with a body part.
2>12.5mmFingers or similar objects.
3>2.5mmTools, thick wires, etc.
4>1mmMost wires, screws, etc.
5Dust ProtectedIngress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment; complete protection against contact.
6Dust TightNo ingress of dust; complete protection against contact.

Second Digit: Liquids

Protection of the equipment inside the enclosure against harmful ingress of water.

LevelObject size protected againstEffective against
0Not protected
1Dripping waterDripping water (vertically falling drops) shall have no harmfull effect.
2Dripping water when tilted up to 15°Vertically dripping water shall have no harmful effect when the enclosure is tilted at an angle up to 15° from its normal position.
3Spraying waterWater falling as a spray at any angle up to 60° from the vertical shall have no harmful effect.
4Splashing waterWater splashing against the enclosure from any direction shall have no harmful effect.
5Water jetsWater projected by a nozzle (6.3mm) against enclosure from any direction shall have no harmful effects.
6Powerful water jetsWater projected in powerful jets (12.5mm nozzle) against the enclosure from any direction shall have no harmful effects.
7Immersion up to 1mIngress of water in harmful quantity shall not be possible when the enclosure is immersed in water under defined conditions of pressure and time (up to 1 m of submersion).
8Immersion beyond 1mThe equipment is suitable for continuous immersion in water under conditions which shall be specified by the manufacturer. Normally, this will mean that the equipment is hermetically sealed. However, with certain types of equipment, it can mean that water can enter but only in such a manner that it produces no harmful effects.