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IP Ratings and their Meanings

27 Sep 2019
Carole Lawlor
IP Ratings and their Meanings

IP ratings are a scale that show us how protected electro-technical devices or their components are.

IP ratings were developed (by International Electrotechnical Commission) to demonstrate the quality of protection in electrical devices from external mechanical influences such as solid influence or liquid influence (most commonly, dust and water).  Since the scale was created and where thorough testing has taken place by authorised bodies every individual electrical device will have an IP rating which highlights their resistance to external influences.

The two criteria will have a combination of letters IP and two other numbers that represent two different sections of the scale depending on the level of the protection:


1st digit – Protection against Solid Influence

Level sized Effective against Description
X X means there is no data available to specify a protection rating with regard to this criteria.
0 No protection against contact and ingress of objects
1 >50 mm Any large surface of the body, such as the back of a hand, but no protection against deliberate contact with a body part
2 >12.5 mm Fingers or similar objects
3 >2.5 mm Tools, thick wires, etc.
4 >1 mm Most wires, slender screws, large ants etc.
5 Dust protected Ingress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment.
6 Dust tight No ingress of dust; complete protection against contact (dust tight). A vacuum must be applied. Test duration of up to 8 hours based on air flow.


2nd digit – Protection against Liquid Influence

Level Protection against Effective against
0 None
1 Dripping water Dripping water (vertically falling drops) shall have no harmful effect on the specimen when mounted in an upright position onto a turntable and rotated at 1 RPM.
2 Dripping water when tilted at 15° Vertically dripping water shall have no harmful effect when the enclosure is tilted at an angle of 15° from its normal position. A total of four positions are tested within two axes.
3 Spraying water Water falling as a spray at any angle up to 60° from the vertical shall have no harmful effect, utilizing either: a) an oscillating fixture, or b) A spray nozzle with a counterbalanced shield.
    Test a) is conducted for 5 minutes, then repeated with the specimen rotated horizontally by 90° for the second 5-minute test. Test b) is conducted (with shield in place) for 5 minutes minimum.
4 Splashing of water Water splashing against the enclosure from any direction shall have no harmful effect, utilizing either: a) an oscillating fixture, or b) A spray nozzle with no shield.
    Test a) is conducted for 10 minutes. Test b) is conducted (without shield) for 5 minutes minimum.
5 Water jets Water projected by a nozzle (6.3 mm) against enclosure from any direction shall have no harmful effects.
6 Powerful water jets Water projected in powerful jets (12.5 mm nozzle) against the enclosure from any direction shall have no harmful effects.
6K Powerful water jets with increased pressure Water projected in powerful jets (6.3 mm nozzle) against the enclosure from any direction, under elevated pressure, shall have no harmful effects. Found in DIN 40050, and not IEC 60529.
7 Immersion, up to 1 m depth Ingress 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).
8 Immersion, 1 m or more depth The equipment is suitable for continuous immersion in water under conditions which shall be specified by the manufacturer. 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. The test depth and duration is expected to be greater than the requirements for IPx7, and other environmental effects may be added, such as temperature cycling before immersion.
9K Powerful high temperature water jets Protected against close-range high pressure, high temperature spray downs.
    Smaller specimens rotate slowly on a turntable, from 4 specific angles. Larger specimens are mounted upright, no turntable required, and are tested freehand for at least 3 minutes at distance of 0.15–0.2 m.
    There are specific requirements for the nozzle used for the testing.
    This test is identified as IPx9 in IEC 60529.
(All tests with the letter "K" are defined by ISO 20653 (replacing DIN 40050-9) and are not found in IEC 60529, except for IPx9 which is the same as the IP69K water test.)



Alongside these numbers there may also be some letters depending on additional information that the manufacturer feels is appropriate to provide.  The letters are based on the following:

Letter Meaning
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


To summarise, if the unit has IP67 rating it means that the unit is dust tight and no solid particles can affect its operation and it can handle water immersion up to 1m (time should be defined by manufacturer).  If the unit has IP57 it doesn’t mean that the unit is for 10 something below on the scale, but it’s below for only 1 level and makes the unit dust proof but not dust tight – for example it can be used outdoor and in various dusty environments but not for example a factory using flour on the production floor where is a constant high concentration of solid air particles.

If the unit doesn’t have an IP rating it means it’s not tested for the rating as it’s not legal requirement for it to have the rating.

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