ISO 2574:1994

Overview

ISO 2574:1994 - "Aircraft - Electrical cables - Identification marking" specifies standardized methods for marking single‑core, multi‑core and coaxial aircraft cables to record type, size, origin, manufacturer and date. Its purpose is to improve traceability for servicing, fault investigation and safe replacement with equivalent parts. The standard supplements national and other marking standards and references ISO 3166 country codes for origin identification.

Key topics and requirements

• Legend content: Markings must include the cable name or specification number, type and size, country of origin (ISO 3166 alpha‑2), a manufacturer code (one‑letter, assigned nationally) and a year‑of‑manufacture code (per the standard’s table).
• Marking format & frequency: The legend is printed in green or a contrasting colour with character sizes per national standards and repeated on the cable at defined intervals (document specifies 300 mm and 50 mm intervals).
• Core identification methods:
  • Colour coding Methods 1A, 1B, 1C - predefined insulation colour sequences and stripe rules for up to and beyond 10 cores.
  • Method 2 - coloured rings on insulation (ring widths and placement prescribed).
  • Method 3 - printed Arabic numerals on white insulation for sequential core numbering.
• Coaxial cable marking: Outer jacket marking to include the coaxial standard number and country/manufacturer/year codes.
• Large or irregular cables: For cables >14 mm2 (AWG 6) or irregular cross‑sections that cannot be marked, coloured threads encode year and manufacturer (thread colours and material must withstand rated temperatures).
• Normative reference: ISO 3166 (country codes) is cited for origin coding.

Example formats shown in the standard: EN 2266 - 003 - 006 and DE - R 91

Applications and users

ISO 2574 is essential for:

• Aircraft OEMs and wire harness manufacturers - to ensure consistent cable identification during production.
• Maintenance, Repair & Overhaul (MRO) teams and avionics technicians - for rapid fault diagnosis, maintenance records and safe cable replacement.
• Suppliers and quality managers - for traceability, batch control and regulatory compliance.
• Certification and regulatory authorities - to verify traceable identification practices in wiring systems.

Practical benefits include faster fault isolation, reduced risk of incorrect cable substitution, improved lifecycle recordkeeping, and harmonized international communication about cable origin and age.

Related standards

• ISO 3166 (codes for country names) - normative reference used to identify countries of origin.
• ISO 2574 is intended to supplement national cable marking standards and other aerospace electrical standards; users should apply the most recent national and IEC/ISO cable specifications where referenced.