This part of AS/NZS 60079 specifies requirements for the construction, testing and marking for Group II electrical apparatus with type of protection, ‘‘n’‘ intended for use in explosive gas atmospheres. This part is applicable to non-sparking electrical apparatus and also to electrical apparatus with parts or circuits producing arcs or sparks or having hot surfaces which, if not protected in one of the way specified in this Standard, could be capable of igniting a surrounding explosive gas atmosphere. This Standard describes several different methods by which this can be achieved which may be combined with other methods described in AS/NZS 60079.0. This part supplements the general requirements in AS/NZS 60079.0.