EN 50020:1994

This European Standard specifies the construction and testing of intrinsically safe apparatus, intended for use in potentially explosive atmospheres and for associated apparatus, which is intended for connection to intrinsically safe circuits which enter such atmospheres. This European Standard supplements EN 50014: 1992 Electrical apparatus for potentially explosive atmospheres - general requirements edition 1992, the requirements of which apply to intrinsically safe apparatus and to associated apparatus with some exceptions. If associated apparatus is protected by a type of protection listed in EN 50014 then the requirements of that method of protection together with the relevant Parts of EN 50014 also apply to the associated apparatus. The list of exclusions which follows is directly applicable to associated apparatus intended for use in situations where there is no potentially hazardous atmosphere and in other circumstances should be used in combination with the requirements of the other methods of protection. This standard is applicable to electrical apparatus in which the electrical circuits themselves are incapable of causing an explosion in the surrounding explosive atmosphere. This standard is also applicable to electrical apparatus or parts of electrical apparatus located outside the potentially explosive atmosphere or protected by another type of protection listed in EN 50014, where the intrinsic safety of the electrical circuits in the potentially explosive atmosphere may depend upon the design and construction of such electrical apparatus or parts of such electrical apparatus. The electrical circuits exposed to the potentially explosive atmosphere are evaluated for use in such an atmosphere by applying this standard. Note: methods of interconnection of intrinsically safe apparatus and associated apparatus are specified in EN 50039