EN 3660-012:2008

Overview

EN 3660-012:2008 is a European product standard developed by the Aerospace and Defence Industries Association of Europe (ASD-STAN) for aerospace series cable outlet accessories. Specifically, it defines the specifications for grommet nut, style A used with circular and rectangular electrical and optical connectors compliant with EN 3372. This standard addresses manufacturing, dimensional, material, and testing requirements for these grommet nuts utilized primarily in demanding aerospace environments.

The grommet nuts covered under this standard are associated with electrical connectors specified in EN 3660-002 and are designed to operate reliably across stringent temperature ranges:

• Class N: –65 °C to 200 °C
• Class W: –65 °C to 175 °C

This ensures suitability in aerospace applications where extreme thermal conditions are typical.

Key Topics

• Product Scope and Compatibility
  Grommet nuts style A are accessories for cable outlets on circular and rectangular connectors. They interface with connectors following EN 3660-002, providing dust and environmental sealing as well as mechanical durability.

• Dimensions and Interface Specifications
  Exact dimensions and parameters such as thread size, mass, coupling nut dimensions, teeth configuration, and wire lock hole placements are prescribed to maintain interchangeability and performance standards. Sizes range from shell size 08 to 24, with precise measurements detailed in the standard.

• Material and Surface Finish

  • Class N: Aluminium with electroless nickel plating, offering corrosion resistance and durability for high-temperature applications.
  • Class W: Aluminium with olive drab cadmium plating, suitable for slightly lower temperature ranges with added environmental protection.

• Mechanical and Environmental Requirements
  The grommet nuts must meet stringent torque specifications for installation and testing purposes, ensuring secure mechanical connections.
  Comprehensive testing protocols include:

  • Visual and dimensional examinations
  • Electrical conductivity and impedance measurements
  • Thermal endurance and resistance to rapid temperature changes
  • Environmental resistance such as salt mist, dust, ozone, fluid, and fire resistance tests
  • Mechanical shock, vibration, and endurance testing

• Marking and Designation
  Clear marking conventions are established to ensure traceability, conformity, and ease of identification in assembly and maintenance.

Applications

EN 3660-012:2008 grommet nuts are essential components in the aerospace industry's electrical and optical connector systems. Their applications include:

• Aircraft Electrical Wiring Systems
  Protecting cable outlets from mechanical strain and environmental factors while ensuring reliable electrical or optical connections within aircraft.

• Spacecraft and Satellites
  With their wide temperature tolerance and rigorous testing, these grommet nuts are suitable for harsh environments in space applications.

• Defense and Military Aerospace Equipment
  Used in ruggedized communication and control systems demanding high durability and performance under extreme conditions.

• High-Performance Engineering Systems
  Any application requiring precision connectors with assured mechanical and environmental integrity can benefit from these standardized grommet nuts.

Related Standards

• EN 3660-002: Defines the associated electrical connector series for which these grommet nuts are designed.
• EN 3660-001: Technical specification for cable outlet accessories including testing procedures referenced in EN 3660-012.
• EN 2591: Aerospace standard defining test methods used to qualify the product's mechanical and environmental performance.
• AS85049: SAE standard for connector accessories, providing further interface compatibility details.

Keywords: EN 3660-012, aerospace grommet nut, cable outlet accessories, circular connectors, rectangular connectors, electrical connectors, optical connectors, aerospace cable accessories, connector sealing, aerospace standards, electroless nickel plating, cadmium plating, aerospace temperature range, mechanical testing aerospace, EN 3660-002, EN 3660-001.