A wire harness is typically designed to simplify the manufacture of a larger component, and is designed based on the geometric and electrical requirements of the equipment it is to be installed in.

Wire harnesses are commonly used in the electronics industry, the automotive industry, in the manufacture of construction machinery and industrial equipment, as well as in the manufacture of white goods such as washing machines and dryers, refrigerators, and other household appliances.

The wire harness simplifies the building of these larger components by integrating the wiring into a single unit, or several units, for “drop-in” installation. By binding the many wires, cables, and subassemblies into a harness, the OEM or installer only has one component to install. In addition, a wire harness allows the completed assembly to be better secured against the effects of abrasion and vibration, and by constricting the wires into a non-flexing bundle, usage of space is optimized.

Once a design is established, the process of building a wire harness starts with the development of a schematic that is used to create the manufacturing paperwork and the assembly board for the harness. The assembly board, or pin board, is a full size diagram of the harness and shows all of the components and their location and also serves as the workbench for the harness. The wires needed for the harness are supplied on a master reel and are cut to the desired length and identified with printing or labeling if necessary. Once cut to the proper length, the wires are stripped to expose the uninsulated conductor and then fitted with any required terminals or connector housings. These wires and components then are put on the pin board and are bound together by any necessary straps, cable ties, cable lacing, sleeves, tapes, weaves of extruded string, or any combination of these.

In spite of the desire to increase automation, wire harnesses, in general, continue to be manufactured by hand because of the many different processes involved.