An IP Rating or Ingress Protection Code consists of the letters IP followed by two digits and an optional letter. This environmental test is defined in the international standard IEC 60529. The standard calls out the degrees of protection an electric enclosure provides against the intrusion of solid objects and liquids. The standard provides a repeatable procedure to identify and name the protection a product enclosure provides and gives validity to marketing terms such as weather proof or splash proof. Some product standards call for an IP test from the standpoint of ensuring user safety from fire or electrical shock, but more and more manufacturers are asking for the test simply to prove out a design method and give validity to the descriptions used in marketing material.
The two numbers indicate conformity with the conditions summarized in the graphic herein.
First Digit: Solids
The first digit indicates the level of protection that the enclosure provides against access to hazardous parts (e.g., electrical conductors, moving parts) and the ingress of solid foreign objects. Solids includes body parts like hands and fingers as well as solids as tiny as a speck of dust.
Second Digit: Liquids
The second number rates the protection of the equipment inside the enclosure against harmful ingress of water. Water can be presented to the enclosure in the form of a low volume accidental drip to something as harsh as a high pressure water jet.