What are IP & NEMA ratings?

Ingress Protection (IP) ratings are developed by the European Committee for Electro Technical Standardization (CENELEC).

An IP number is used to specify the environmental protection of enclosures around electronic equipment against the intrusion of solid objects or dust, accidental contact or water. These ratings are determined by specific tests that is meant to provide more detailed information than vague terms, such as "water-proof".

The IP number is composed of two numbers, the first number referring to the protection against solid objects and the second number referring to the protection against liquids. The higher the number, the better the protection.

Attached is a brief description of IP and NEMA ratings: