I.S. 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

Provides requirements for d.c. switchgear and controlgear and is intended to be used in fixed electrical installations with nominal voltage not exceeding 3000 V d.c. which supply electrical power to vehicles for public guided transport, i.e. railway vehicles, tramway vehicles, underground vehicles and trolley-buses.