EEx e Protection for electrical components that do not spark under normal working conditions but where measures are applied to prevent high temperatures and the occurrence of arcs and sparks internally. EEx ia Protection for equipment containing intrinsically safe circuits, which are incapable of causing an explosion in the surrounding atmosphere, that is where current and voltage in normal operation would not produce enough spark energy or heat to ignite any potentially explosive gases or dusts. EEx d Protection for equipment containing parts which can ignite an explosive atmosphere and that designed to withstand the pressure developed during an internal explosion and prevent the explosion being transmitted to the atmosphere surrounding the enclosure. EEx n Similar (but not as stringent) to EEx e, this non-sparking protection concept when applied to electrical aparatus such that, in normal and in certain specified abnormal conditions, it is not capable of igniting a surrounding explosive gas or dust atmosphere. Several varieties of this concept can be applied, Ex nA, nR, nC, nL, nZ. :: Protection Concepts :: Temperature Class :: Zone Classification :: Equipment Groups