An IP (Ingress Protection) rating is a standardised classification defined by IEC 60529 that tells you precisely how well an electrical enclosure resists the intrusion of solid particles and liquids.
Developed by the International Electrotechnical Commission (IEC), IP ratings replace vague marketing terms like "waterproof" or "dustproof" with a consistent, testable scale used across the electrical and electronics industry. Whether you are specifying industrial cable glands for a harsh outdoor environment, selecting enclosures for control gear, or simply buying a smartphone, the IP code tells you exactly what level of protection has been verified, and under what conditions. Understanding how to read that code takes less than two minutes.
How to Read an IP Rating
An IP rating consists of two digits. The first indicates protection against solid bodies; the second indicates protection against liquids. A rating of IP65, for example, means the enclosure is fully dust-tight (6) and protected against water jets from any direction (5). If one digit is unknown or not applicable, it is replaced with an X. For instance, IPX4 indicates a tested liquid ingress rating with no solid particle rating declared.
First Numeral: Protection Against Solid Bodies
The first digit runs from 0 to 6 and describes the degree to which the enclosure prevents solid objects from entering and reaching live or hazardous parts.
|
Rating |
Protection |
|
0 |
No protection |
|
1 |
Protected against solid bodies greater than 50mm (e.g. involuntary hand contact) |
|
2 |
Protected against solid bodies greater than 12mm (e.g. fingers) |
|
3 |
Protected against solid bodies greater than 2.5mm (e.g. tools, cables) |
|
4 |
Protected against solid bodies greater than 1mm (e.g. small tools, fine cables) |
|
5 |
Protected against dust, no harmful deposits |
|
6 |
Fully protected against dust |
Ratings 1 through 4 primarily address personal safety, preventing accidental contact with live parts. Ratings 5 and 6 address environmental contamination, with IP6X being the highest achievable dust rating under IEC 60529.
Second Numeral, Protection Against Liquids
The second digit runs from 0 to 8 and describes the enclosure's resistance to water ingress under defined test conditions.
|
Rating |
Protection |
|
0 |
No protection |
|
1 |
Protected against dripping water (condensation) |
|
2 |
Protected against falling water up to 15° from the vertical |
|
3 |
Protected against rainwater up to 60° from the vertical |
|
4 |
Protected against water splashing from all directions |
|
5 |
Protected against water jets from all directions |
|
6 |
Protected against powerful water jets from all directions |
|
7 |
Protected against immersion |
|
8 |
Protected against the effects of prolonged immersion under water |
Each rating is defined by specific test parameters, water flow rate, pressure, duration, and angle, set out in IEC 60529. It is worth noting that the ratings are not strictly cumulative: an IPX7 enclosure is not necessarily tested to IPX6 conditions. Where both jet resistance and immersion resistance are required, this should be specified explicitly.
Choosing the Right IP Rating
The correct IP rating for any application depends on the environment in which the equipment will be installed in. As a general guide: indoor, dry locations may only require IP20; external or exposed industrial environments typically require IP65 or above; submerged or wash-down applications require IP67 or IP68. Always refer to the full test conditions in IEC 60529 when specifying for critical applications, as the rating alone does not describe every variable under which the enclosure was tested.