This European Standard contains the requirements for construction and testing of Group I intrinsically safe electrical systems intended for use, as a whole or in part, in atmospheres susceptible to firedamp. 1.2 This European Standard supplements EN 50020, the requirements of which apply to electrical apparatus used in intrinsically safe electrical systems. It is intended to apply to - systems placed on the market by a manufacturer or their authorised representative, or - systems assembled by the user, using products separately conforming with EN 50020. 1.3 This European Standard does not deal with the selection of suitable equipment, or the installation of intrinsically safe electrical apparatus, associated electrical apparatus, to form an intrinsically safe electrical system.