IEC 61991:2019

Overview

IEC 61991:2019 - "Railway applications - Rolling stock - Protective provisions against electrical hazards" sets international requirements for the design and manufacture of electrical installations and equipment on rolling stock to protect persons from electric shock. Applicable to rail, magnetically levitated transport, and road transport vehicles powered by an external supply (e.g., trolley buses), this second edition (2019) supersedes the 2000 edition and is based on EN 50153:2014. Key updates include replaced reference standards, new terms/abbreviations, and added annexes for national conditions and impedance management.

Key topics and technical requirements

• Voltage band classification: Defines voltage bands and their application to protective design (see Tables in the standard).
• Protection against direct contact: Prescribes methods such as insulation, prevention of access, and use of ELV systems (SELV, PELV), plus warning labels where required.
• Protection against indirect contact: Requirements for protective bonding, equipotential connections, and disconnection strategies to limit touch voltages and fault currents.
• Disconnection of supply: Functional and timing characteristics for fault disconnection to ensure safety.
• Vehicle main protective bonding: Rules for bonding paths, impedance limits and treatment of contact-line faults.
• Power circuits: Guidance for circuits insulated from, or using, the vehicle body or bogie.
• Additional requirements: Specific rules for current collectors, capacitors, plug-and-socket devices (portable and intervehicle), and special power sources.
• Annexes:
  • Annex A: Items where contracting parties must choose between procedural or mechanical/electrical measures.
  • Annex B: Special national conditions (examples: France, Great Britain, Japan).
  • Annex C: Example solutions for impedance management in EMUs (preventing return-current absorption).

Practical applications and users

IEC 61991:2019 is essential for:

• Rolling stock designers and electrical engineers designing vehicle electrical systems.
• Manufacturers of traction equipment, onboard power systems, connectors, and current collectors.
• System integrators, safety and compliance teams, and maintenance personnel implementing protective bonding and insulation strategies.
• Regulatory authorities, certification bodies, and procurement teams specifying safety compliance in contracts.

Using IEC 61991 ensures consistent protection against electrical hazards across rolling stock fleets, supports safe design choices (insulation, SELV/PELV, bonding), and helps manage interoperability and national variations via Annex B.

Related standards

• EN 50153:2014 (basis for this edition)
• Other IEC norms referenced within IEC 61991 (see normative references in the standard)

Keywords: IEC 61991:2019, railway applications, rolling stock, electrical hazards, protective provisions, electric shock protection, SELV, PELV, equipotential bonding, voltage bands, EMU impedance management.