1.1 This European Standard contains the specific requirements for construction and testing of intrinsically safe electrical apparatus, type of protection 'i', intended for use in potentially explosive atmospheres.
1.2 This European Standard supplements European Standard EN 50 014 'General requirements', the requirements of which apply to intrinsically safe electrical apparatus, and to associated electrical apparatus except for those which concern:
2.1 Electrical apparatus
5.2 Delay times for opening of enclosures
6 Plastics enclosures (for associated electrical apparatus)
7 Light alloy enclosures (for associated electrical apparatus)
8.1 Access to uninsulated live parts
8.2 Special fasteners
9 Interlocking devices
10 Bushings
11 Materials used for cementing
12 Connections
14.3 Terminal compartments
15 Cable and conduit entries
Section III Particular requirements for specific electrical apparatus
22.4.3.1 Test for resistance to impact
22.4.3.3 Rubbing of moving parts
22.4.5 Torque test for bushings
22.4.6 Thermal tests (for associated electrical apparatus) 22.4.6.1
(paragraph 2) Temperature measurements
22.4.7 Insulation resistance test of parts of enclosures of plastics materials (for associated electrical apparatus)
22.4.9 &
22.4.10 Tests for cable entries
If associated electrical apparatus is protected by a type of protection listed in European Standard EN 50 014 'General requirements', the requirements of that standard apply in the conditions of application of the European Standard for the type of protection concerned.
1.3 This European Standard applies to electrical apparatus in which the electrical circuits themselves are incapable of causing explosion in the surrounding atmosphere.
1.4 This European Standard applies also to electrical apparatus or parts of electrical apparatus located outside the potentially explosive atmosphere or protected by another type of protection listed in European Standard EN 50 014 'General requirements', 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.
NOTE. The permitted methods of interconnection of intrinsically safe electrical apparatus and associated electrical apparatus are specified in another European Standard (in preparation).
SIS SS EN 50 020-1983 history
1983SIS SS EN 50 020-1983 Electrical apparatus for potentially explosive atmospheres - Intrinsic safetv ?i?