Ex d Flameproof Enclosures Motors with sliprings & commutators 3 phase squirrel cage motors Equipment that could ignite an explosive atmosphere housed within a substantial enclosure without transmitting internal explosion to surroundings
Ex e Increased Safety 3 or 1 phase rotor with cage rotor Current & voltage transformers Increased measures taken to prevent generation of arcs, sparks & excessively hot areas in equipment, preventing risk of explosion inside/outside of enclosure
Ex i Intrinsic Safety Switches, plugs & socket, terminal boxes Energy is limited to this equipment in such a way that a spark or a hot surface would not be hot enough to ignite the explosive atmosphere