South Australian Numbered Regulations South Australian Numbered Regulations40—Electrical wiring, components, connections and installations
(1) The wiring of electrical equipment of a vehicle, except the high tension ignition wiring, must—
(a) be supported at intervals of not over 600 millimetres, unless the vehicle is a pole-type trailer with a pole with an adjustable length, or an extendible trailer; and
(b) be insulated at each of its joints; and
(c) be located where it cannot—
(i) become overheated; or
(ii) contact moving parts; or
(iii) come near enough to the fuel system to be a fire hazard; and
(d) be protected from chafing.
(2) The electrical components of a vehicle must be securely mounted.
(3) The electrical connectors between motor vehicles and trailers, for operation of the vehicle lights required by the Light Vehicle Standards, must comply with at least 1 of the following standards:
(a) Australian Standard AS 4177.5-2004 Caravan and Light Trailer Towing Components—Part 5: Electrical Connectors ;
(b) International Standards Organisation ISO 1185-1997;
(c) Society of Automotive Engineers SAE J 560-1998.
(4) A trailer must be equipped with an electrical conductor, independent of the trailer coupling, that provides a return path between the electrical circuits of the trailer and towing vehicle.