Overview - ISO 5867-1:1996 (electromagnetic relays and contactors for aircraft)
ISO 5867-1:1996 specifies general performance requirements for electromagnetic relays and contactors intended for aircraft electrical systems. It covers devices designed for nominal 28 V d.c. or 115 V/200 V 3‑phase, 400 Hz a.c. systems (system characteristics as per ISO 1540) and applies to relays/contactors with nominal contact ratings of 5 A a.c., 5 A d.c. or greater. The standard defines construction, environmental, electrical and mechanical requirements, plus qualification and test principles.
Key topics and technical requirements
- Voltage and ratings: Coil operation at 28 V d.c. or 115 V a.c. (400 Hz); contact ratings ≥ 5 A.
- Temperature classes: Three classes - Class A (-65 °C to +125 °C), Class B (-55 °C to +85 °C) and Class C (-55 °C to +70 °C).
- Sealing/enclosure classes:
- Class 1: Hermetically sealed (gas-filled, dew point specified)
- Class 2: Environmentally sealed (purged, inert gas recommended)
- Class 3: Ventilated enclosures (totally enclosed, explosion-proof, dust protection)
- Altitude suitability: Class 1 & 2 up to 25 000 m; Class 3 up to 15 000 m.
- Design and materials: Corrosion-resistant metals, restrictions on certain platings for hermetic parts; non‑metals must be moisture‑resistant, flame/arc resistant and non‑toxic.
- Terminals and grounding: Threaded studs for >25 A, plug‑in or screw for ≤25 A; terminal seat current density limit 1.55 × 10^6 A/m² (1 000 A/in²); secure grounding provisions and terminal covers/barriers required.
- Detail specification sheets: Manufacturers must provide individual spec sheets defining dimensions, terminal markings, dual‑coil relationships and installation/torque values.
- Qualification and tests: Product examination, environmental, electrical and mechanical tests and production acceptance/qualification inspections are specified.
Applications and who uses this standard
ISO 5867-1 is used by:
- Aircraft manufacturers and systems integrators for power distribution, switching and control functions.
- Avionics and relay/contactors manufacturers designing components for 28 V DC and 115/200 V 400 Hz AC aircraft systems.
- Certification engineers, procurement and quality teams validating component compliance and qualification.
- Maintenance and repair organizations referencing performance and installation requirements.
Typical applications include flight‑critical switching, auxiliary power circuits, contactor modules for generators/transformers, and general onboard circuit control in commercial and military aircraft.
Related standards
- ISO 1540 - Aerospace electrical system characteristics (referenced for system parameters)
- ISO 7137 - Aircraft environmental conditions and test procedures
- IEC references (IEC 50 (446), IEC 68‑2‑17, IEC 158‑2) are cited for terminology and test methods.
Keywords: ISO 5867-1:1996, electromagnetic relays, contactors, aircraft relays, 28 V DC, 115 V 400 Hz, aerospace electrical standards, hermetic sealing, relay qualification.