Basics of nomenclature, short forms and abbreviations

IEC : International Electrotechnical Commission

ATEX : ATmosphere EXplosibles

ia : Very High Protection Level - safe after two consecutive malfunctions

ib : High Protection Level - safe after one malfunction

ic : Normal Protection Level - safe under normal operation conditions

Ex : Explosion Proof, Explosion Protected, Ex Proof, Ex Rated

Ex i : Intrinsic safety

Ex d : Flameproof