1987IEC TR 60079-15:1987 Electrical apparatus for explosive gas atmospheres. Part 15 : Electrical apparatus with type of protection "n"
IEC TR 60079-15:1987 Electrical apparatus for explosive gas atmospheres. Part 15 : Electrical apparatus with type of protection "n" was changed to IEC 60079-15:2001 Electrical apparatus for explosive gas atmospheres - Part 15: Type of protection "n".