IEC 60077-3:2019

Overview

IEC 60077-3:2019 - Railway applications - Electric equipment for rolling stock - Part 3: Electrotechnical components - Rules for DC circuit-breakers - provides the electrotechnical rules, requirements and test methods for DC circuit‑breakers used on rolling stock. It applies to main contacts connected to DC power and auxiliary circuits with nominal voltages up to 3 000 V DC (per IEC 60850). This second edition (2019) replaces the 2001 edition and introduces key updates to temperature‑rise verification, adds an air‑tightness type test and includes insulation‑resistance measurement.

Key topics and technical requirements

• Scope and rated values
  • Applicability to DC circuit‑breakers for railway rolling stock (main and auxiliary circuits up to 3 000 V DC).
  • Definitions of rated voltages, rated currents and rated time constants.
• Service conditions
  • Requirements for normal service operation, behaviour under short‑circuit conditions and dielectric performance.
• Constructional and performance requirements
  • Mechanical and electrical construction rules, clearances and creepage distances, EMC and acoustic emission limits, vibration and shock resistance.
  • Temperature‑rise limits and verification procedures.
  • Requirements for switching overvoltages and peak arc voltages.
• Short‑circuit capability
  • Rules for rated short‑circuit making and breaking capacities, including test circuits and verification methods (see Annexes A and B).
• Testing program
  • Defined type tests, routine tests, and investigatory tests with test sequences (I–VI) to validate constructional and performance characteristics.
  • New/updated tests in this edition: air‑tightness as a type test (for pneumatic circuit‑breakers) and insulation resistance measurement.
• Product information & marking
  • Required documentation and marking information to accompany circuit‑breakers for safe selection, installation and maintenance.

Practical applications and users

Who uses IEC 60077-3:2019:

• Rolling stock OEMs and designers specifying DC circuit‑breakers for trains, trams and metros.
• Circuit‑breaker manufacturers designing components to meet railway safety, EMC and environmental criteria.
• Test laboratories and certification bodies performing type and routine testing and conformity assessment.
• Procurement and maintenance teams ensuring installed components meet interoperability, safety and serviceability requirements.

Practical uses:

• Specifying breaker performance (making/breaking capacity, temperature behavior).
• Validating designs against railway environmental and short‑circuit scenarios.
• Creating test plans for type approval and production quality control.

Related standards

• IEC 60077-1 and IEC 60077-2 (general requirements and specific component rules for rolling stock).
• IEC 60850 (reference for nominal DC voltages).
• The broader IEC 60077 series for railway electric equipment.

Keywords: IEC 60077-3:2019, DC circuit-breakers, railway applications, rolling stock, electrotechnical components, short-circuit testing, dielectric properties, temperature rise, air‑tightness, insulation resistance.