What does the second number in an IP rating indicate?

The second number in an IP rating specifically refers to water resistance. In the context of Ingress Protection (IP) ratings, which are used to measure the effectiveness of enclosures against the intrusion of foreign objects and moisture, each digit provides distinct information. The first digit denotes the level of protection against solid particles, such as dust, while the second digit indicates how well the device can withstand water exposure.

For example, if an IP rating is IP67, the "6" indicates complete protection against dust ingress, and the "7" indicates that the device can endure immersion in water up to a certain depth for a specified duration. This makes the second number crucial for applications where moisture exposure is a concern, such as in outdoor cameras or devices used in wet environments. Understanding this distinction is essential for choosing the right equipment based on the environmental conditions it will face.