ISO 8056-3:1987 PDF

Overview - ISO 8056-3:1987 (thermocouple extension cables, crimp ring terminals)

ISO 8056-3:1987 is part of the ISO 8056 series that standardizes nickel‑chromium (Ni‑Cr) and nickel‑aluminium (Ni‑Al) thermocouple extension cables for aircraft. This Part 3 specifies the dimensions for crimp‑type ring terminal ends used with flexible thermocouple extension cables in aircraft temperature indicator and control systems. The standard applies to systems at a nominal voltage of 600 V and a maximum frequency of 2 000 Hz, and it defines conductor size ranges and cable insulation ranges for correct connector selection and installation.

Key topics and requirements

• Dimensional definitions for crimp‑type ring terminal ends (stud hole sizes and maximum/minimum body and sleeve dimensions).
• Conductor size range and corresponding cable insulation range to ensure reliable crimping and electrical continuity.
• Sleeve color coding and magnetic properties: Ni‑Al (green, magnetic) and Ni‑Cr (grey, antimagnetic) identification to prevent interchange of dissimilar thermocouple materials.
• Compatibility references: includes references to conductor sizing in AWG and metric threads (e.g., for M5 and M6 screws) where applicable.
• Interchangeability focus: ensures terminals fit the specified studs and achieve acceptable crimp mechanical and electrical performance when used with the listed cable types.
• Note: General requirements and test methods for terminations are covered in ISO 8056‑2; this document restricts itself to dimensional data.

Practical applications and users

Who uses ISO 8056-3:

• Aircraft electrical and systems engineers specifying thermocouple extension wiring and terminations.
• Cable and connector manufacturers producing crimp ring terminals for aviation thermocouple systems.
• Maintenance, inspection and avionics technicians performing installations or repairs on temperature sensor wiring.
• Procurement and quality assurance teams ensuring purchased components meet aircraft standards and are interchangeable.

Practical benefits:

• Guarantees mechanical fit and electrical compatibility between thermocouple extension cables and ring terminals.
• Reduces risk of misconnection of dissimilar thermocouple materials by color coding and magnetic designation.
• Simplifies certification and maintenance by referencing a recognized international dimensional standard.

Related standards

• ISO 8056‑1: Conductors (part of the same series)
• ISO 8056‑2: Terminations - General requirements and tests (important companion document)
• ISO 8056‑4: Crimp‑type butt connectors - Dimensions

Keywords: ISO 8056-3, thermocouple extension cables, crimp-type ring terminal ends, nickel-chromium, nickel-aluminium, aircraft, dimensions, conductor size, cable insulation, temperature control systems.