EN 3475-305:2002

Overview

EN 3475-305:2002 is a European standard developed by the European Association of Aerospace Manufacturers (AECMA) and published by CEN. It specifies a test method for measuring the overload resistance of finished electrical cables used in aircraft. This standard is part of a broader aerospace cable series focused on ensuring the safety, reliability, and performance of electrical wiring systems in aerospace applications.

The standard must be used in conjunction with EN 3475-100, which covers general test methods for aerospace cables. EN 3475-305:2002 details the procedure for subjecting cable specimens to electrical overload conditions to evaluate their resistance, smoke emission, insulation integrity, and overall durability when exposed to elevated conductor temperatures.

Key Topics

• Scope
  Defines the test method for finished aerospace electrical cables to assess overload resistance under controlled conditions.

• Specimen Preparation

  • Cable specimens of 0.75 m to 1 m length are mounted horizontally, lightly stretched to avoid slack.
  • Testing is carried out at ambient temperature in a draft-free chamber.
  • A device or screen with black and white bands is used to detect smoke and visual changes.

• Testing Methodology

  • The test involves applying electrical current to raise the conductor to two specified temperatures (T1 and T2), defined within the product standard.
  • Temperature control is monitored by measuring voltage drop along the cable.
  • The conductor is first maintained at temperature T1 for 30 minutes, then increased to temperature T2 for 15 minutes.
  • The test checks for smoke emission, insulation damage, and any ignition risks during and after overload exposure.

• Acceptance Criteria

  • At temperature T1: No visible smoke, smell, or color change should occur.
  • At temperature T2: No visible insulation deterioration such as cracking, peeling, or conductor stripping, and no spontaneous combustion or smoke is permissible.

Applications

• Aerospace Electrical Cable Testing
  EN 3475-305:2002 is essential for manufacturers and quality assurance teams designing and producing electrical cables for aircraft, helicopter, and spacecraft use.

• Safety and Reliability Assurance
  This standard provides a rigorous testing framework to ensure cables can withstand electrical overloads without compromising safety or performance, minimizing risks of cable failure in critical aerospace environments.

• Component Qualification
  Aerospace component suppliers use this standard during product development and certification to demonstrate compliance with overload resistance requirements.

• Maintenance and Inspection Protocols
  Maintenance teams can reference this method as part of inspection procedures to evaluate cable integrity after suspected electrical overload events.

Related Standards

• EN 3475-100: Aerospace series - Cables, electrical, aircraft use - Test methods - Part 100: General
  Provides overarching general test procedures applicable to aerospace cables, and must be used together with EN 3475-305.

• Other Parts of EN 3475 Series
  Covers additional test methods related to electrical properties, environmental resistances, and mechanical strength of aerospace cables.

• AECMA Standards for Aerospace Wiring
  Broader guidelines and standards governing aerospace electrical wiring systems, often referenced alongside EN 3475 tests.

Keywords: Aerospace cables, electrical cables aircraft use, overload resistance testing, EN 3475-305, aerospace wiring standards, cable smoke emission test, electrical cable insulation, aerospace test methods, aircraft cable safety, European aerospace standards, CEN standards.