is the European standard for Degrees of protection provided by enclosures (IP Code) . It’s identical to IEC 60529 (international) and defines IP ratings like IP67, IP68, etc. It specifies:

The standard is an internationally recognized framework that defines the degrees of protection provided by enclosures for electrical equipment . Often searched as "EN 60529 PDF," this document serves as the technical foundation for the IP (Ingress Protection) Code , a system used to classify how well a device is sealed against solid objects, dust, and water. Overview of EN 60529

Search for "EN 60529:1991 + A2:2013 official PDF" and buy from IEC or BSI. Avoid free PDF hosting sites unless you are certain the document is an unmodified, complete, and current version – and even then, use only for internal learning, never for legal compliance.

Protection against the harmful ingress of water. First Numeral: Solid Objects & Dust Ingress Protection (IP) ratings - IEC