The worldwide electrotechnical standard for electrical equipment for explosive atmospheres is covered by two major"standards":

  • IEC/CENELEC (1) (common standard following agreement in 1991
    on procedures for developing standards).
  • NEC (2) (products approved by UL, FM, etc).

Products which conform to IEC/CENELEC or NEC standards have identical protection, even though they are designed differently to meet specific installation regulations. IEC can be considered as the "international standard" accepted in nearly every country.

The 1996 edition of the NEC, article 505, uses the IEC names for gas groups, equipment temperature classes and area definitions.
To obtain more detailed information, contact the national laboratories : LCIE (France), INERIS (France), ISSEP (Belgium), BASEEFA (United Kingdom, PTB (Germany), etc...

1) IEC: International Electrotechnical Commission & CENELEC:
European Committee of Electrotechnical Standards.
2) NEC : National Electrical Code.