EN 3841-406:2004

Overview

EN 3841-406:2004 - Aerospace series: Circuit breakers - Test methods - Part 406: Flammability - is a CEN-adopted European standard that specifies a method to verify the flammability of plastic (synthetic) materials used in circuit breaker housings, insulator bases and any parts exposed to arcs or glowing elements. The procedure is based on the glow-wire test and is intended for aerospace electrical equipment where fire safety and material performance under arcing conditions are critical.

Key topics and technical requirements

• Scope: Applies to plastics used in the housing, insulator base and parts that may be exposed to electrical arcs or glowing elements of circuit breakers.
• Normative reference: Test method references IEC 60695-2-10 (Glow/Wire Apparatus and Common Test Procedure).
• Test setup: Uses the glow-wire apparatus described in IEC 60695-2-10 with the following specific requirements:
  • Tip of the glow-wire positioned (200 ± 5) mm above the white board (board ≈ 10 mm thick, covered with a single layer of tissue paper).
  • Test applies to parts supporting current-carrying conductors (main and signal) and parts of housing likely to contact arcs.
  • Glow-wire tip temperature: (960 ± 15) °C.
  • Duration of application: (30 ± 1) s.
• Pass/fail criteria:
  • Any flame or glowing of the tested part must be extinguished within 30 s after removal of the glow-wire.
  • No ignition of the tissue paper placed beneath the specimen.

Practical applications and users

• Who uses this standard:
  • Aerospace manufacturers and suppliers of circuit breakers and protective devices.
  • Design and materials engineers selecting plastics for housings and insulating components.
  • Test laboratories performing flammability and fire-hazard testing for avionics and aircraft electrical equipment.
  • Regulatory compliance officers, quality assurance and procurement teams verifying vendor compliance with aerospace safety standards.
• Why it matters:
  • Ensures materials resist ignition from arcing and glowing elements, reducing risk of fire propagation on aircraft.
  • Supports component qualification, supplier approval, and type or production testing for aerospace circuit breakers.
  • Integrates with broader safety and certification efforts for avionics and electrical systems.

Related standards

• IEC 60695-2-10 - Fire Hazard Testing: Glow/Wire apparatus and common test procedure (normative reference for the glow-wire method).
• EN 3841 series - other parts addressing circuit breaker test methods (see national or CEN listings for related parts and test procedures).

Keywords: EN 3841-406:2004, flammability test, aerospace circuit breakers, glow-wire test, IEC 60695-2-10, plastic housings, insulator base, fire safety testing.