IP ratings, or Ingress Protection ratings, consist of a coding system which is used to classify the extent to which enclosures are susceptible to intrusion by solid foreign bodies, such as fingers or dust, and liquids. It’s purpose was to enable the industry to move away from inaccurate descriptions of enclosures i.e. splash proof. This IP Rating classification method was outlined by the International Electrotechnical Commission (IEC Standard 60529), and is recognised in most European countries.
A common misconception about IP ratings is that the higher the number the better the protection. This classification system can be misleading, not only because appropriate IP ratings are dependent upon the enclosure’s application, but also because the two digits indicate separate criteria.
The first digit in the rating is indicative of the enclosures protection against the ingress of solids whereas the second digit classifies the extent to which the enclosure is protected against liquids. In common practice when an enclosure is not rated, or rating has been omitted due to irrelevance, numbers are replaced by the character “X”. IP numerical values and their significance are detailed in the infographic below.