IP classes: what do they really mean?
The international standard IEC 60529 defines a system for assessing the resistance of equipment and enclosures to environmental factors.
The IP code indicates how well the housing protects the device from solid foreign objects and liquids.
IP classification is mainly used to determine the protection of enclosures of electrical and electronic devices.
1. Level of protection against foreign objects (first digit of the IP code)
The first number indicates the size of foreign objects the device is protected against entering the housing.
| First number | Protection description |
|---|---|
| 0 | The housing does not protect against foreign objects. |
| 1 | Protects against objects ≥ 50 mm. |
| 2 | Protects against objects ≥ 12.5 mm (e.g. finger). |
| 3 | Protects against objects ≥ 2.5 mm (e.g. tools, wires). |
| 4 | Protects against objects ≥ 1.0 mm (small tools, wires). |
| 5 | Protects against dust so that it does not interfere with the operation of the device (partial dust protection). |
| 6 | The housing is completely dustproof. |
2. Level of protection against liquids (second digit of the IP code)
The second number determines the amount and direction of water the device is protected against.
Tests are performed with clean water — other liquids (oils, chemicals) may give different results.
| Second number | Protection description |
|---|---|
| 0 | Does not protect against liquids. |
| 1 | Protects against vertically falling water drops. |
| 2 | Protects against falling water drops at an angle of up to 15°. |
| 3 | Protects against water splashes falling at an angle of up to 60°. |
| 4 | Protects against water splashes from all directions. |
| 5 | Protects against water jets coming from all directions. |
| 6 | Protects against strong water jets. |
| 7 | Protects against short-term immersion in water. |
| 8 | Protects against continuous immersion in water or according to the conditions specified by the manufacturer. |
3. IP code example
If a device is marked IP34 , this means:
-
3 – protection against foreign objects ≥ 2.5 mm
-
4 – protection against water splashes from all sides
This type of device is suitable for normal environments, but is not intended for continuous contact with water.
4. IP X and additional letters
The letter X in the IP code indicates that this property has not been tested.
Examples:
-
IPX6 – tested against water jets, dust protection not tested
-
IP6X – tested for dust, not tested for water protection
Additional characters (optional)
| Star | Explanation |
|---|---|
| A | Protection against touching hazardous parts with your hands. |
| B | Protection when touched with a finger. |
| C | Protection when touching with tools. |
| D | Protection against touching the wire. |
| H | The device is intended for use at voltages above 1000 V. |
| M | Water resistance test conducted in a moving state. |
| S | Water resistance test performed in a stationary state. |
| W | Weatherproof, suitable for outdoor use. |
Summary
The IP code gives a quick overview of the protection level of a device:
-
First digit – protection against solid particles and dust
-
Second number – protection against water and liquids
The exact characteristics of the protection always depend on the test conditions and operating environment specified by the manufacturer.
In extreme or chemically aggressive conditions, you should always check the manufacturer's documentation or choose a solution with a higher protection class.
