EN 50102 : 1995: degrees of protection provided by enclosures for electrical equipment against external mechanical impacts (IK code) / European Commitee for Electrothecnical Standardization
Electrical installations of buildings : part 4: protection for safety: chapter 44: protection against overvoltages: section 442: protection of low-voltage installations against faults between high-voltage systems and earth: HD 384 .4.442 S1: January 1997 / European Commitee for Electrothecnical Standardization