NF C23-579-15:2006 Electrical apparatus for explosive gas atmospheres - Part 15 : construction, test and marking of type of protection "n" electrical apparatus.
2006NF C23-579-15:2006 Electrical apparatus for explosive gas atmospheres - Part 15 : construction, test and marking of type of protection "n" electrical apparatus.
2004NF C23-579-15:2004 Electrical apparatus for explosive gas atmospheres - Part 15 : type of protection "n".
2000NF C23-521:2000 Electrical apparatus for potentially explosive atmospheres - Type of protection "n".