IP Rating

An IP rating is a system that classifies the protection of an item against solids and liquids.

It is also known as an IP Code, International Protection Marking or more popularly as Ingress Protection. It is also the European Standard EN 60529.

The rating is split into two digits. The first being protection against solid particles, eg: dust. The second digit is for liquid ingress protection eg: water. Each digit represents an escalating level of protection. On the first digit, the number 0 offers no protection while 6 would be dust tight. The second digit can range from 0 giving no protection against water, upto an extreme of 9 which is protection against powerful high temperature water jets (typically overkill for standard devices).

A typical IP rating found on one of our floodlights would be: IP65

The first digit means that the item is dust tight, allowing for no ingress of dust whatsoever. The second digit means the item is protected against water jets, Water projected by a nozzle (6.3 mm) against enclosure from any direction shall have no harmful effects.

The following are IP Ratings charts for both digits in the rating.

Solid Object/Particle Protection (First Digit)

 Rating   Solid / Particle Size  Protection Against
X X means there is no data available to classify a protection rating.
0 No protection against contact and ingress of solid/particle 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, tacks, large ants etc.
5 Dust protected Ingress of dust is not fully 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 or fine particulates; complete protection against contact (dust tight). 

Liquid Protection (Second Digit)

 Rating Level of ProofingProtection 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, or condensation.
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. 
3 Spraying water Water falling as a spray at any angle up to 60° from the vertical shall have no harmful effect.
4 Splashing of water Water splashing against the enclosure from any direction shall have no harmful effect.
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 greater pressure Water projected in powerful jets (6.3 mm nozzle) against the enclosure from any direction, under elevated pressure, shall have no harmful effects.
7 Immersion, up to 1 meter 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 meter or more depth 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. 
9K Powerful high temperature water jets Protected against close-range high pressure, high temperature spray downs. There are specific requirements for the nozzle used for the testing.

References

IEC 60529, Edition 2.2, 2013, page 19

IEC 60529, Edition 2.2, 2013, page 21

Wikipedia Article regd IP Code

Table 8, IEC 60529, Edition 2.2, 2013