An IP rating is useful as it defines how well an enclosure protects its contents from outside factors in a specific and precise way, rather than relying on generic or vague terms such as ‘waterproof’ or ‘dustproof’. Testing the enclosures of products is important for safety purposes and to ensure product performance. It also gives buyers and sellers confidence in the safety and functionality of the IP rated product. IP ratings can be seen on everything from Bluetooth speakers to the protective cases for military equipment, but what does the rating actually indicate?

What is an IP rating and how is it broken down?

An IP rating (also called an Ingress Protection or International Protection Rating) is a two-digit grading system that’s given to an enclosure of a mechanical or electrical item to indicate how effectively the device is sealed against the intrusion of foreign bodies such as liquids. IP ratings always carry the same format, for example ‘IP35’ or ‘IP68’.

The IP rating system is actually very simple and easy to interpret. It starts with the letters IP. Then the first digit, ranging from 0 to 6, indicates the level of protection against solids. This includes any solid foreign objects, such as tools or fingers, that could cause damage to any electrical or moving parts within the enclosure. The second digit

ranges from 0 to 8 and refers to the level of protection against liquids. This shows protection against various levels of moisture exposure, from the natural elements to full submersion. Essentially, the higher the rating, the more effective the sealing.

If either of these digits is replaced by an X, it means that the enclosure has not been tested or the test is not applicable, not that the item offers no protection from liquids or solids. A rating of 0 in either category indicates no protection.

IP testing

The IP testing process is demanding and is performed under different pressures and temperatures to ensure satisfactory results. Testing for the sealing effectiveness of an enclosure is an important part of the research and development phase of a product. Unsurprisingly, most issues with the sealing effectiveness of enclosures arise with the seam between two parts. For many products, IP testing is not a requirement for all products, but sellers will often ask manufacturers to include an IP rating for their products before they include it in their inventory. There are different standards and methods used to test for the IP rating of a product to different specifications, but every testing system will yield the same standardised IPXX format rating. The method of testing will depend on the manufacturer.

IP ratings for solids

The rating scale for protection from solid particles is usually displayed in an IP rating chart and is as follows:

0 – No protection

1 – Protected against a solid object greater than 50mm, e.g. a hand

2 – Protected against a solid object greater than 12.5mm, e.g. a finger

3 – Protected against a solid object greater than 2.5mm, e.g. a screwdriver

4 – Protected against a solid object greater than 1mm, e.g. a wire

5 – Dust protected, i.e. limited ingress of dust permitted and this will not interfere (2-8 hours)

6 – Dust-tight, i.e. no ingress of dust (2-8 hours)

IP waterproof ratings: IP ratings for liquids

To measure waterproofness, enclosures are subjected to drip, spray, rain, continuous stream, depth and submersion testing. An enclosure’s level of resistance to moisture is rated as follows:

0 – No protection

1 – Protected against vertically falling water drops

2 – Protected against vertically falling water drops when at 15° from its normal position

3 – Protected against water spraying up to 60° on either side

4 – Protected against spraying at any angle

5 – Protected against powerful water jets or heavy seas

6 – Protected against water jets (hosepipe) from any directions

7 – Protected against submersion in water under defined conditions of pressure and time

8 – Protected against continuous submersion in water

Occasionally, an IP rating might include an additional letter at the end of the code, for example, IP24D. This simply gives extra information about the protection against specific materials or hazards provided by the enclosure:

D – Wire

F – Oil resistant

H – High voltage device

M – Device moving during water test

S – Device standing still during water test

W – Weather conditions