Overview
ISO 11446-1:2012 specifies the mechanical and electrical requirements for 13‑pole connectors used to make the electrical connection between towing and towed vehicles with a 12 V nominal supply voltage where vehicles are not intended to cross water fords. The standard covers dimensional characteristics, contact allocation and designation, mechanical features (plug, socket and park socket), terminal sizes, and references required tests and performance criteria.
Key topics and requirements
- Connector type: 13‑pole plug, mating socket and a park socket for storing the plug when disconnected. Covers floating contacts that align to a datum position on engagement.
- Dimensions and mechanical design: Detailed dimensions for plug, socket and park socket; cover shown open must close automatically when plug is disconnected. Minimum cover opening angle is 135°. Twist‑lock torque specified between 1 N·m and 3.5 N·m.
- Contact allocation and designation: Contact numbering and functions (e.g., 1 = left indicator, 6 = stop lights, 8 = reversing light, 9 = permanent +12 V, 10 = switched +12 V, 12 = reserved). Contact numbers must be permanently marked inside the socket cover and on terminal faces. Important note: the three separate return circuits shall not be connected electrically in the trailer.
- Electrical terminals and cables: Terminal rear pins/tubes accept nominal cable cross‑sections: 1.5 mm² for most lighting circuits (contacts 1,2,4,5,6,7,8) and 2.5 mm² for power/return contacts (3,9,10,11,13). Connecting cables must meet the applicable part of ISO 4141.
- Testing and performance: Connectors shall be tested per ISO 4091 and meet its requirements (electrical, mechanical and environmental tests as referenced).
- Mounting/clearances: Connector positions and free space are specified in relation to coupling dimensions (see ISO 1103).
Applications and users
ISO 11446-1 is intended for:
- Automotive OEMs (cars, vans, light trucks) specifying trailer electrical interfaces
- Trailer and caravan manufacturers and aftermarket towbar suppliers
- Electrical connector and cable harness manufacturers
- Test laboratories and certification bodies performing compliance checks
- Fleets, RV and towable equipment designers who require standardized tow wiring
Adopting ISO 11446-1 ensures interoperability, safer trailer lighting/power connections and clearer supplier specifications for 13‑pole, 12 V towing connectors.
Related standards
- ISO 11446-2 (13‑pole connectors for vehicles intended to cross water fords)
- ISO 4091 (definitions, tests and requirements for towing connectors)
- ISO 4141 (multi‑core connecting cables)
- ISO 1103 (coupling ball dimensions for caravans and light trailers)
Open preview (PDF)Road vehicles — Connectors for the electrical connection of towing and towed vehicles — Part 1: 13-pole connectors for vehicles with 12 V nominal supply voltage not intended to cross water fords