SIST EN 3475-504:2004

Overview

EN 3475-504:2002 specifies a standardized torsion test method for evaluating the resistance to damage of insulated conductors and finished cables used in aerospace applications. Prepared under AECMA and adopted by CEN, this European standard defines specimen preparation, test apparatus, test cycles, and acceptance criteria for torsional damage. It is intended to be used together with EN 3475-100 (general test-method requirements).

Keywords: EN 3475-504, torsion test, aerospace cables, electrical aircraft cables, torsion resistance, cable test methods, insulated conductors, finished cables.

Key Topics and Requirements

• Scope: Method for checking resistance to damage under torsion of insulated conductors or finished cables (aerospace use).
• Reference: Must be used in conjunction with EN 3475-100 for general test conditions and definitions.
• Specimen preparation:
  • Length: 250 mm specimen.
  • Pre-ageing: 50 hours in an oven at temperature T4 (value specified in the product standard).
• Apparatus:
  • Two axially aligned clamps holding the specimen taut.
  • One clamp capable of rotating ±360° about the specimen axis to apply torsion and untwisting.
  • The opposite clamp free to move axially (but not rotate) to maintain tension under a load defined in the product specification.
  • Test assembly is placed in a temperature-controlled chamber at T3 (specified in the product standard).
• Test cycle and speed:
  • One torsion cycle = 360° rotation in one direction, then 720° in the opposite direction, then 360° back to zero.
  • 100 cycles are performed at 5–6 cycles per minute.
• Acceptance criteria:
  • After testing and removal from the chamber, a visual inspection of the specimen is performed.
  • Any debonding of layers, along the insulation or at the ends, is considered a defect.

Applications and Users

• Who uses it:
  • Aerospace manufacturers, cable designers, quality and test laboratories, procurement and certification bodies, and maintenance/repair organizations.
• Practical uses:
  • Qualification and acceptance testing of electrical aircraft cables and insulated conductors.
  • Design verification for cable assemblies expected to undergo torsional stresses in service.
  • Supplier control and batch testing to ensure compliance with aerospace reliability requirements.
  • Supporting regulatory and certification documentation for aircraft electrical systems.

Related Standards

• EN 3475-100 - Aerospace series – Cables, electrical, aircraft use – Test methods – Part 100: General (normative reference for EN 3475-504).

This standard provides a concise, reproducible torsion test procedure to assess torsional durability and bonding integrity of aerospace electrical cables - essential for reliable aircraft electrical systems.