The IP rating system is a standard used to define the levels of ingress protection for electronic equipment. The system consists of two numbers, IPXX, the first of which denotes the level of protection against solids, and the second against liquids. The higher the number, the greater the level of protection. IP68, for example, is a common rating that is often seen on electrical enclosures. It is the highest protection level, the digit 6 indicates that the enclosure is totally protected against solid dust ingress, and digit 8 shows that it can withstand depths greater than 1 meter for 30 minutes or more. Another commonly seen IPX rating is IPX7, which means there’s no rating for the solids ingress portion. But it can be submerged in up to one meter of water for up to 30 minutes.