ISO 8668-2:1986

Overview

ISO 8668-2:1986 - Aircraft - Terminal junction systems - Part 2: Tests specifies the test procedures and performance requirements for aircraft terminal junction systems referenced in ISO 8668-1. It defines how to verify electrical, mechanical and environmental characteristics of removable terminal junction modules (connectors) used in aircraft wiring and equipment. This part is intended to be read in conjunction with ISO 8668-1 (characteristics) and cites IEC 68-2 environmental test procedures.

Key topics and technical requirements

• Test scope: A comprehensive set of electrical, mechanical and climatic tests for terminal junction systems, with pass/fail criteria given in the standard’s tables.
• Electrical tests
  • Internal continuity checks and insulation resistance measurements (document states a minimum insulation resistance value of 5 000 Ma as listed).
  • Dielectric/voltage withstand: progressive a.c. voltage up to 1 500 V r.m.s. held for specified duration; leakage current limits apply.
  • Contact resistance tests (low-voltage and rated-current methods) using a four‑terminal measurement method described in the annex; procedures for measuring voltage drop across contacts are detailed.
• Mechanical tests
  • Contact insertion/extraction force, contact retention in the insulator and mechanical endurance cycles.
  • Mechanical shock (half‑sine 981 m/s², 6 ms / 100 g, three shocks per axis) and vibration (10–2 000 Hz, specified amplitude, 12 h total) with continuity monitoring.
• Climatic and environmental tests
  • Dry heat, damp heat (steady-state and cyclic), salt spray (48 h), immersion/pressure cycles and ozone exposure, plus resistance-to-fluids procedures.
  • Contact resistance stability under mechanical movement (swinging positions) and service-like contamination/grease conditions.
• Measurement details: Annex specifies copper conductors, wire stripping and attachment, four‑terminal setup and sealing compounds for reliable contact-resistance and voltage-drop readings.

Applications and users

ISO 8668-2 is used by:

• Aircraft components and electrical connector manufacturers for design verification and production acceptance testing.
• Certification and qualification engineers validating connector performance for avionics and aircraft wiring harnesses.
• Maintenance, procurement and quality assurance teams specifying test requirements in detail specifications or supplier contracts.
• Test houses that perform environmental, mechanical and electrical verification to aerospace standards.

Related standards

• ISO 8668-1: Characteristics (read jointly with Part 2)
• IEC 68-2 series (basic environmental testing procedures) - referenced for vibration, shock, heat, damp heat, salt mist and other environmental tests.

Keywords: aircraft terminal junction systems, contact resistance, voltage drop measurement, insulation resistance, connector testing, ISO 8668-2, environmental testing, aviation electrical connectors.