IEC 60079-25:2010

FOREWORD
1 Scope
2 Normative references
3 Terms, definitions and abbreviations
4 Descriptive system document
5 Grouping and classification
6 Levels of protection
7 Ambient temperature rating
8 Interconnecting wiring/cables used in an intrinsically
   safe electrical system
9 Requirements of cables and multi-core cables
10 Termination of intrinsically safe circuits
11 Earthing and bonding of intrinsically safe systems
12 Protection against lightning and other electrical surges
13 Assessment of an intrinsically safe system
14 Marking
15 Predefined systems
Annex A (informative) - Assessment of a simple intrinsically
        safe system
Annex B (normative) - Assessment of circuits with more
        than one source of power
Annex C (informative) - Interconnection of non-linear and
        linear intrinsically safe circuits
Annex D (normative) - Verification of inductive parameters
Annex E (informative) - A possible format for descriptive
        systems drawings and installation drawings
Annex F (informative) - Surge protection of an intrinsically
        safe circuit
Annex G (normative) - Testing of cable electrical parameters
Annex H (informative) - Use of simple apparatus in systems
Annex I (normative) - FISCO systems
Bibliography

IEC 60079-25:2010 contains the specific requirements for construction and assessment of intrinsically safe electrical systems, type of protection "i", intended for use, as a whole or in part, in locations in which the use of Group I, II or III apparatus is required. This standard supplements and modifies the general requirements of IEC 60079-0 and the intrinsic safety standard IEC 60079-11. Where a requirement of this standard conflicts with a requirement of IEC 60079-0 or IEC 60079-11, the requirement of this standard takes precedence. This standard supplements IEC 60079-11, the requirements of which apply to electrical apparatus used in intrinsically safe electrical systems. The installation requirements of Group II or Group III systems designed in accordance with this standard are specified in IEC 60079-14. The significant changes with respect to the previous edition are:
- extension of the scope from Group II to Groups I, II and III;
- introduction of level of protection "ic";
- addition of requirements for cables and multi-core cables;
- reference to IEC 60079-11 regarding the termination of intrinsically safe circuits;
- requirements for the assessment of an expanded and clarified intrinsically safe system regarding level of protection "ic", simple apparatus and faults in multi-core cables;
- introduction of predefined systems and merging of the system requirements for FISCO from IEC 60079-27;
- addition of requirements for simple intrinsically safe systems containing both lumped inductance and lumped capacitance;
- addition of a method for testing the electrical parameters of cables;
- additional information for the use of simple apparatus in systems.
The contents of the Interpretation Sheet 1 of May 2023 have been included in this copy.