IEC 60077-5:2019

Overview

IEC 60077-5:2019 - Railway applications: Electrotechnical components - Rules for HV fuses defines supplemental rules for high-voltage (HV) fuses used in rolling stock. It is a Part 5 supplement to IEC 60077-2 and must be read alongside IEC 60077-1. The standard covers HV fuses for power and auxiliary circuits with nominal DC voltages between 600 V DC and 3 000 V DC (per IEC 60850) and allows use in auxiliary AC circuits up to 1 500 V. Edition 2.0 (2019) replaces the 2003 edition and notably revises the test method for test duty III used to verify breaking capacity.

Key topics and technical requirements

The standard specifies the technical characteristics, service conditions and test methods for HV fuses used on railway rolling stock. Main topics include:

• Characteristics of HV fuses
  • Rated voltage and current, breaking range and utilisation category
  • Time–current characteristics and conventional times (e.g., “g” characteristics)
• Service conditions
  • Behaviour in normal service, short-circuit operation and dielectric performance
  • Temperature-rise limits and environmental conditions relevant to rolling stock
• Constructional and performance requirements
  • Requirements for fuse-links, fuse-bases, contacts and external terminals
  • Mechanical and electrical construction criteria to ensure safe operation in traction environments
• Verification and testing
  • Type tests, routine tests and investigatory tests
  • Breaking capacity tests (including revised Test Duty III), dielectric tests and temperature-rise tests
  • Test sequences and tolerances, and test circuit guidance (annexes provide diagrams and calibration details)
• Product information and marking
  • Documentation, marking and information to be supplied with the fuse for conformity and field use

Practical applications

IEC 60077-5:2019 is used to:

• Specify and approve HV fuses for traction power circuits and auxiliary systems on locomotives, EMUs and other rolling stock.
• Define factory and type-test programs for manufacturers and independent test laboratories to demonstrate compliance (breaking capacity, dielectric strength, temperature rise).
• Inform procurement and maintenance teams when selecting fuse types, verifying time–current coordination and ensuring safe behavior under short-circuit conditions.
• Support system designers in applying correct utilisation categories, rated voltages and installation instructions for HV fuses in DC traction systems and auxiliary AC circuits.

Who should use this standard

• Railway electrical designers and OEMs
• HV fuse manufacturers and test laboratories
• Rolling stock maintenance engineers and procurement/specification teams
• Certification bodies and conformity assessors involved in railway electrification and traction equipment

Related standards

• IEC 60077-1 / IEC 60077-2 (general rules and electrotechnical components)
• IEC 60850 (voltages for railway rolling stock)
• IEC 60269-1 and IEC 60282-1 (fuse rules considered during drafting)

Keywords: IEC 60077-5:2019, HV fuses, railway applications, rolling stock, high voltage fuses, breaking capacity, dielectric properties, time–current characteristics.