The IP protection category is characterised by 2 numbers:
Degrees of protection for protection against contact and foreign bodies: First characteristic numeral
First characteristic numeral | Description | Explanation |
1 | Protected against solid foreign objects with a diameter of 50 mm and greater | The object probe, a sphere 50 mm in diameter, must not penetrate fully 1). |
2 | Protected against solid foreign objects with a diameter of 12.5 mm and greater | The object probe, a sphere 12.5 mm in diameter, must not penetrate fully 1). The articulated test finger may penetrate up to its length of 80 mm, but adequate distance must be adhered to. |
3 | Protected against solid foreign objects with a diameter of 2.5 mm and greater | The object probe, a sphere 2.5 mm in diameter, must not penetrate at all 1). |
4 | Protected against solid foreign objects with a diameter of 1.0 mm and greater | The object probe, a sphere 1.0 mm in diameter, must not penetrate at all1). |
5 | Dust-protected | The ingress of dust is not fully prevented, but dust may not enter to such an extent as to impair satisfactory operation of the device or safety. |
6 | Dust-tight | No ingress of dust at a partial vacuum of 20 mbar inside the enclosure. |
1) The full diameter of the object probe shall not pass through an opening of the enclosure.
Degrees of protection for protection against water: Second characteristic numeral
Second characteristic numeral | Description | Explanation |
1 | Protected against vertically falling water drops | Vertically falling drops shall have no harmful effects. |
2 | Protected against vertically falling water drops when the enclosure is tilted up to 15° | Vertically falling drops must not have any harmful effects when the enclosure is tilted up to 15° on either side of the vertical. |
3 | Protected against spraying water | Water sprayed at an angle of up to 60° on either side of the vertical shall have no harmful effects. |
4 | Protected against splashing water | Water splashed on the enclosure from any direction shall have no harmful effects. |
5 | Protected against water jets | Water directed at the enclosure from any direction in a jet shall have no harmful effects. |
6 | Protected against powerful water jets | Water directed at the enclosure from every direction in a powerful jet shall have no harmful effects. |
7 | Protected against the effects of temporary immersion in water | Water must not ingress to such an extent as to cause harmful effects when the enclosure is temporarily immersed in water under standardised pressure and time conditions. |
8 | Protected against the effects of continuous immersion in water | Ingress of water in quantities causing harmful effects shall not be possible when the enclosure is continuously immersed in water under conditions to be agreed between the manufacturer and the user. However, the conditions must be more difficult than for characteristic numeral 7. |
9 | Water during high-pressure/steam-jet cleaning | Water directed at the enclosure from every direction under greatly increased pressure must not have any adverse effects. |
Example of a protection category, e.g. IP 43:
First characteristic numeral = 4:
Protected against solid foreign objects with a diameter of 1.0 mm and greater
Second characteristic numeral = 3:
Protected against spraying water