The IP ratings were introduced as a standard the aim being to provide the user with more detailed information rather than the former use of vague terms as waterproof, water resistant, dust resistant.
The IP Code, International Protection marking, ratings are defined in the international standard IEC standard 60529. They are used to define levels of sealing effectiveness of electrical enclosures or housings, from intrusion of foreign bodies (tools, hands and fingers, etc) and also its water ingress resistance .
There are usually two numbers in the IP rating the first number indicates the degree of mechanical protection this can be to protect the user from moving parts but also to protect the enclosed equipment from ingress by particles, tools or dust etc. The second number indicates the degree of moisture protection in various forms such as condensation water spray or submersion.
The table set out below gives the definitions for each number. Any number replaced by x indicates the enclosure is not rated for that specification.