National foreword
Committees responsible
Guide
Introduction
1. General considerations
1.1 Scope
1.2 Object
2. General considerations concerning the nature of
electric contact and the calculation of the ohmic
resistance of contacts
2.1 Electric contacts and connection terminals
2.2 Calculation of contact resistance
3. Ageing mechanism of contacts and connection
terminals
3.1 General
3.2 Contacts of dissimilar metals
3.3 Oxidation ageing mechanisms
3.4 Results concerning ageing of contacts
3.5 Usage and precautions to be taken in the use of
contact materials
4. Calculation of temperature rise of conductors,
contacts and connection terminals
4.1 Definitions
4.2 Temperature rise delta Ts of a conductor with
respect to the temperature Te of the surrounding
medium
4.3 Temperature rise delta T0 in the vicinity of the
contact: temperature rise of connection terminals
4.4 Temperature rise of the elementary contact points
4.5 Numerical example
5. Permissible temperature and temperature rise values
5.1 Definitions
5.2 Temperature and temperature rise of various
equipment components
5.3 Temperature and temperature rise of conductors
connecting electrical equipment
5.4 Temperature and temperature rise of connection
terminals for electrical equipment - Influence on
connected conductors
6. General procedure to be followed for determining
permissible temperature and temperature rise
6.1 Basic parameters
6.2 Method to be followed for determining maximum
permissible temperature and temperature rise
6.3 Chart for determining maximum permitted temperature
or temperature rise
References
Appendix A: Characteristics of selected metals and alloys
Appendix B: Physical characteristics of certain
dielectrics
Appendix C: Information on the reaction of contact metals
with substances in the atmosphere
Appendix D: Bolted (screwed) terminals and connections:
recommended clamping torques
Appendix E: Insulation classes
Appendix F: List of letter symbols used
Appendix G: Derivation of an equation representing the
temperature rise of a conductor in the vicinity of a
terminal, in the case of cooling by radiation and natural
convection