A cable harness, also known as a wire harness, cable assembly, wiring assembly or wiring loom,
is a string of cable

Cable

A cable is two or more wires running side by side and bonded, twisted or braided together to form a single assembly. In mechanics cables, otherwise known as wire ropes, are used for lifting, hauling and towing or conveying force through tension. In electrical engineering cables are used to carry...

s and/or wires

Electrical wiring

Electrical wiring in general refers to insulated conductors used to carry electricity, and associated devices. This article describes general aspects of electrical wiring as used to provide power in buildings and structures, commonly referred to as building wiring. This article is intended to...

 which transmit informational signals or operating currents (energy). The cables are bound together by clamps

Clamp (tool)

A clamp is a fastening device to hold or secure objects tightly together to prevent movement or separation through the application of inward pressure...

, cable ties, cable lacing, sleeves, electrical tape

Electrical tape

Electrical tape is a type of pressure-sensitive tape used to insulate electrical wires and other material that conduct electricity. It can be made of many plastics, but vinyl is most popular, as it stretches well and gives an effective and long lasting insulation...

, conduit

Electrical conduit

An electrical conduit is an electrical piping system used for protection and routing of electrical wiring. Electrical conduit may be made of metal, plastic, fiber, or fired clay. Flexible conduit is available for special purposes....

, a weave of extruded string, or a combination thereof.

Commonly used in automobiles, as well as construction machinery, modern-day cable harnesses provide several advantages over loose wires and cables. For example, many aircraft, automobiles and spacecraft contain many masses of wires which would stretch over several kilometres if fully extended. By binding the many wires and cables into a cable harness, the wires and cables can be better secured against the adverse effects of vibrations, abrasions, and moisture. By constricting the wires into a non-flexing bundle, usage of space is optimized, and the risk of a short is decreased. Since the installer has only one harness to install (as opposed to multiple wires), installation time is decreased and the process can be easily standardized. Binding the wires into a flame-retardant sleeve also lowers the risk of electrical fires.

Production

Cable harnesses are usually designed according to geometric and electrical requirements. A diagram is then provided (either on paper or on a monitor) for the assembly preparation and assembly.

The wires are first cut to the desired length, usually using a special wire-cutting machine. The wires may also be printed on by a special machine during the cutting process or on a separate machine. After this, the ends of the wires are stripped to expose the metal (or core) of the wires, which are fitted with any required terminals

Terminal (electronics)

A terminal is the point at which a conductor from an electrical component, device or network comes to an end and provides a point of connection to external circuits. A terminal may simply be the end of a wire or it may be fitted with a connector or fastener...

 and/or connector housings

Electrical connector

An electrical connector is an electro-mechanical device for joining electrical circuits as an interface using a mechanical assembly. The connection may be temporary, as for portable equipment, require a tool for assembly and removal, or serve as a permanent electrical joint between two wires or...

. The cables are assembled and clamped together on a special workbench

Workbench

A workbench is sturdy table at which manual work is done. They range from simple flat surfaces to very complex designs that may be considered tools in themselves. Workbenches vary in size from tiny jewelers benches to the huge benches used by staircase makers...

, or onto a pin board (assembly board), according to the design specification, to form the cable harness. After fitting any protective sleeves, conduit, or extruded yarn, the harness is either fitted directly in the vehicle or shipped.

In spite of increasing automation

Automation

Automation is the use of control systems and information technologies to reduce the need for human work in the production of goods and services. In the scope of industrialization, automation is a step beyond mechanization...

, in general, cable harnesses continue to be manufactured by hand, and this will likely remain the case for the foreseeable future. In part, this is due to the many different processes involved, such as:

• routing wires through sleeves,
• taping with fabric tape, in particular on branch outs from wire strands,
• crimping
  Crimp (joining)
  Crimping is joining two pieces of metal or other malleable material by deforming one or both of them to hold the other. The bend or deformity is called the crimp.- Uses :...
  
   terminals onto wires, particularly for so-called multiple crimps (more than one wire into one terminal),
• inserting one sleeve into another,
• fastening strands with tape, clamps or cable ties.

It is clearly difficult to automate these processes. In spite of this, these processes can be learned relatively quickly, even without professional qualifications. Thus, manual production remains more cost effective than automation. For certain vehicles, such as trucks, there are also a large number of variants (due to different configurations and the length of the vehicles), which produce very small batch sizes

Batch

Batch may refer to:Food and drink*Batch , an alcoholic fruit beverage*Batch loaf, a type of bread popular in Ireland*A dialect term for a bread roll used in Nuneaton and Coventry, England*Small batch, bourbon whiskey blended from selected barrels...

 (as low as one). However, the number of variants has been decreasing in recent years due to the use of data bus technology, such as a CAN

Controller Area Network

Controller–area network is a vehicle bus standard designed to allow microcontrollers and devices to communicate with each other within a vehicle without a host computer....

 bus, in conjunction with intelligent control units. In spite of this, different variants are produced on the same assembly board. Even here, man has an advantage over machine, since he can change over to the different variants (no "re-programming" being required).

Pre-production, however, can be automated in part. This affects:

• Cutting individual wires (cutting machine),
• crimping terminals onto one or both sides of the wire,
• partial plugging of wires prefitted with terminals into connector housings (module),
• soldering
  Soldering
  Soldering is a process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the workpiece...
  
   of wire ends (solder machine), and
• twisting
  Twisted pair
  Twisted pair cabling is a type of wiring in which two conductors are twisted together for the purposes of canceling out electromagnetic interference from external sources; for instance, electromagnetic radiation from unshielded twisted pair cables, and crosstalk between neighboring pairs...
  
   wires.

Testing the electrical functionality of a cable harness can be done with the aid of a test board. The circuit diagram

Circuit diagram

A circuit diagram is a simplified conventional graphical representation of an electrical circuit...

 data are pre-programmed into the test board, where harnesses can be tested individually or in multiple numbers.

Cable harnesses in sound engineering

The cable harnesses used in sound engineering (stage and studio) for carrying audio signals

Audio signal processing

Audio signal processing, sometimes referred to as audio processing, is the intentional alteration of auditory signals, or sound. As audio signals may be electronically represented in either digital or analog format, signal processing may occur in either domain...

 are also called multicores.