A two-digit number established by the International Electro Technical Commission, is used to provide an Ingress Protection rating to a piece of electronic equipment or to an enclosure for electronic equipment.
The protection class after EN60529 are indicated by short symbols that consist of the two code letters IP and a code numeral for the amount of the protection.
Example: IP65 (NEMA 4)
The two digits represent different forms of environmental influence:
• The first digit represents protection against ingress of solid objects.
• The second digit represents protection against ingress of liquids.
The larger the value of each digit, the greater the protection. As an example, a product rated IP54 would be better protected against environmental factors than another similar product rated as IP42.