ISO 8056-4:1987

Overview

ISO 8056-4:1987 establishes the dimensional requirements for crimp-type butt connectors used with nickel-chromium and nickel-aluminium thermocouple extension cables in aircraft applications. This part of the ISO 8056 series focuses on connectors intended for temperature indicator and control systems in aviation environments, supporting flexible thermocouple extension cables at a nominal voltage of 600 V and a maximum frequency of 2,000 Hz. The standard specifies the acceptable conductor size range and cable insulation range to ensure compatibility and optimal performance in demanding operational conditions.

Key Topics

• Connector Dimensions: Provides precise measurements for crimp-type butt connectors, ensuring interoperability and compatibility across manufacturers and installations.
• Material Compatibility: Covers connectors used with nickel-chromium and nickel-aluminium thermocouple extension cables, which are commonly used for their stability and resistance to high temperatures.
• Electrical Ratings: Specifies usage with systems up to 600 volts and 2,000 Hz, aligning with typical aircraft temperature sensor and control system requirements.
• Conductor and Insulation Range: Defines the permissible conductor sizes (in mm² and AWG) and corresponding cable insulation diameters, facilitating secure and reliable electrical connections.
• Color Coding: Addresses sleeve color coding by material type (e.g., green for Ni-Al, grey for Ni-Cr) to assist with correct assembly and identification.

Applications

The requirements outlined in ISO 8056-4:1987 are vital across several aviation sectors, including:

• Temperature Monitoring Systems: Ensures reliable electrical connections in temperature indicator and control systems critical to aircraft operation and safety.
• Flexible Cable Installations: Improves the durability and lifespan of flexible nickel-based thermocouple extension cables by specifying connector compatibility.
• Maintenance and Retrofitting: Provides standardized dimensions to enable easy replacement and maintenance of thermocouple extension cables and connectors throughout an aircraft's lifecycle.
• Compliance and Quality Assurance: Assists aircraft manufacturers, suppliers, and maintenance organizations in meeting international quality and performance standards, supporting regulatory compliance and operational reliability.

Related Standards

ISO 8056-4:1987 is part of a series addressing various aspects of nickel-chromium and nickel-aluminium thermocouple extension cables in aircraft:

• ISO 8056-1: Conductors - General requirements and tests
• ISO 8056-2: Terminations - General requirements and tests
• ISO 8056-3: Crimp-type ring terminal ends - Dimensions

Additional related standards include:

• ISO 14675: Aerospace series - Electrical connectors and accessories
• AS9100 series: Aerospace quality management systems
• IEC 60584: Thermocouples - Reference tables and tolerances

Conclusion

ISO 8056-4:1987 delivers essential guidance for the design, selection, and installation of crimp-type butt connectors for nickel-chromium and nickel-aluminium thermocouple extension cables in the aviation industry. By specifying connector dimensions, conductor and insulation range, and color coding, this standard ensures compatibility, safety, and performance in temperature measurement and control systems using flexible cable installations. Adherence to ISO 8056-4 enhances not only operational reliability but also maintenance efficiency and global interoperability in aircraft electrical systems.