EN 50123-1:2003

1 Scope
2 Normative references
3 Definitions
  3.1 General terms
  3.2 Performance characteristics
  3.3 Components
  3.4 Terms relating to d.c. circuit breakers,
      switch-disconnectors and associated relays
4 Service conditions and requirements
  4.1 Environmental conditions
  4.2 Insulation levels
5 Standard features and conventional assumptions
  5.1 Standard features and conventional parameters
      for the main circuit
  5.2 Standard features for auxiliary and control
      circuits
6 Temperature-rise limits
7 Tests
  7.1 General
  7.2 Test tolerances
  7.3 Tests on movable devices
  7.4 Temperature-rise test
  7.5 Dielectric tests
  7.6 Short circuit and load switching conditions
  7.7 Verification of the behaviour during short-time
      withstand current test
  7.8 Verification of the manual control device for
      sturdiness and position indicator reliability
Annex A (normative) Diagrams for tests
Annex B (normative) Environmental conditions for indoor
        installations
Annex C (normative) Search of critical currents for d.c.
        circuit breakers and switches
Annex D (informative) Recommended creepage distances
Annex E (informative) Determination of maximum energy
        fault location
Bibliography
Figures
Tables

The EN 50123 series specifies requirements for d.c. switchgear and controlgear and is intended to be used in fixed electrical installations with nominal voltage not exceeding 3 000 V d.c., which supply electrical power to vehicles for public guided transport, i.e. railway vehicles, tramway vehicles, underground vehicles and trolley-buses.Part 1 specifies general requirements.The other parts are coveringPart 2D.C. circuit breakers,Part 3Indoor d.c. disconnectors, switch-disconnectors and earthing switches,Part 4Outdoor d.c. disconnectors, switch-disconnectors and earthing switches,Part 5Surge arresters and low voltage limiters for specific use in d.c. systems,Part 6 D.C. switchgear assemblies,Part 7 1Measurement, control and protection devices for specific use in d.c. traction systems – Application guide,Part 7 2Measurement, control and protection devices for specific use in d.c. traction systems – Isolating current transducers and other current measuring devices,Part 7 3Measurement, control and protection devices for specific use in d.c. traction systems –Isolating voltage transducers and other voltage measuring devices