DD CLC/TS 50502:2008

1 General
  1.1 Scope
  1.2 Normative references
  1.3 Definitions
  1.4 Voltages
  1.5 Classification of the voltage bands
2 Trolley bus construction
  2.1 Protection and electrical safety criteria
  2.2 Electrical components in band III voltage (high voltage)
  2.3 Electric traction equipment
  2.4 Emergency running equipment (independent from OHL)
  2.5 Electrical components in band II voltage (medium voltage)
  2.6 Electrical components in band I voltage (low voltage)
3 Checks and tests
  3.1 General
  3.2 New trolley vehicles
  3.3 Overhauled trolley vehicles
  3.4 On-duty trolley vehicles (periodical checks)
  3.5 Leakage detectors
Annex A (normative) - Constructional detailed provisions
Annex B (normative) - Trolley buses - Connection system to overhead
        contact lines
Annex C (normative) - Constructional hints for connection systems
Bibliography

Describes the requirements and constructional hints, especially to avoid danger of electrical kind to the public and to the personnel.