Custom-Made Wire Harness: Why Custom Designing Is Best for Wiring Harnesses


You must route and terminate cables and wires to make the machinery functional for electrical equipment, machinery, or control panels. To overcome this problem, you can make cables and wires before the equipment and bundle them together to fit into your equipment or machinery. At this time, you can turn to custom-made wire harnesses.

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Why do we need a custom-made wire harness?

Standard wire harness assemblies may not be able to provide the precision application and reliability necessary in many situations, which is why custom-made ones are so widely used.

Application of custom wire harnesses

You can use wiring harnesses in various electrical and electronic devices in different industries, which include:

  • Agricultural
  • Aerospace
  • Aircraft
  • Industrial equipment
  • Medical
  • Military
  • Industrial vehicle
  • Wire
  • Safety and Security
  • Printing

Advantages of custom wire harness assembly

Custom-made wire harnesses serve multiple benefits for various industries. 


Without harnesses, technicians juggled for hours with wires and cables to ensure the correct installation. However, custom-designed wire harnesses simplify and quicken the installation process.

Better product quality

A wiring harness is mainly an integrated arrangement of wires and cables having an exterior covering. The reins help connect devices to their power source, and the outer sheath protects the components from severe environmental conditions. As different applications have complex requirements, you may need to add cables for shielding, networking, or position feedback into the wire bundles. Apart from the termination of copper wire, an electrical wiring harness can build cable assemblies with their connectors. Usually, you need to tie the saddle with tape or braid or cover them in a sleeve or spiral wrap to make them an integrated assembly.

Customized wiring harnesses have adequate labeling, bundling, and easy-to-identify and install connectors. So, you are sure that products rolling from the assembly line have acceptable quality and are reliable.

High-quality materials

Professional manufacturers of wiring harnesses use high-grade materials in manufacturing wires and cables. If you install such wires, you will receive the best quality of power and signal transmission from your product.

Serves plenty of applications

These custom-made cabling and wiring power modern equipment, used in many industries and applications, serving the toughest of applications.

Additional advantages

Store-bought cables and wires do not come with any other service. However, a custom wiring harness manufacturer will provide additional services like laser stripping, cables and wires marking for easy identification and installation, and custom insulation.

Wire harness components

Wiring harnesses comprise several components available in different forms to suit various applications.

Wire harness wire

Wires are responsible for carrying a signal or current that powers equipment. The capacity of the wire must be higher than the bandwidth or voltage it needs to transmit. Most wires are made of copper, and some may have a special coating also.


There are different shapes and sizes of connectors that help in connecting different wire types. Connectors are either made from plastic, metal, or ceramic.


Fuses help stop the power surge from damaging or overloading the device. There are different classes of fuses. Generally, fuses come in 32 volts or less, but they can vary according to their amperage rating.


Grommets help in keeping moisture away from the connectors. You can attach it to a terminal or a part of a connector.

Insulators or outer covering

These outer covers protect from environmental stress and electrical shocks and resist abrasion. They are either made from nylon or polyolefin.


Relays turn on or off the higher amperage circuits. Further, like fuses, their amperage ratings may vary. As a result, you can power multiple things with the harnesses.

Strain relief

You can attach it to the connector’s outer part. As a result, it will prevent the wire pulling force in the connector from keeping the wire terminal in place. You can also put a strain relief at an outer bend radius.


You must attach the terminals at the wire ends, which you will insert into the connector or attach to a point on connecting equipment.


With clamps and cable ties, you can keep the wires inside the harnesses properly attached to form a stream of cables in a particular direction. Also, you can use it to attach the harness to a structure at a fixed point.

Custom-Made Wire Harness: Locks

You can insert a lock into a connector to prevent the wire terminals from pulling out of the connector. 

Custom-Made Wire Harness: Cables

With specific cable standards, it becomes easy for engineers to design cables with certain specifications, thus saving a lot of money and time. At Cloom, you can find various UL-certified cable types like SVO, SJE, TST, SPT-2, TPT, and many others. Further, we adjust factors such as fillers, insulation, gauges, and sheathing materials to make a cable that matches the exact specifications of your intended application.

Custom-Made Wire Harness: Sleeves

First, velcro sleeves are pretty standard and very easy to secure. Sleeves help in providing resistance to abrasion, Ultraviolet rays and offer proper cable management. The wiring harnesses use various types of sleeves, including:

  • Second, you will find braided sleeves that give an aesthetic look to the cable. You can also heat-shrink this sleeve to any specific connector or cable type.
  • Third, Polyethylene spiral wraps protect cables from heat and general wear and tear.
  • Lastly, polypropylene wraps add strength and resilience to ultraviolet rays. They come in different diameters.
Custom-Made Wire Harness:  wiring harnesses with plastic connectors at a beer plant

Image: wiring harnesses with plastic connectors at a beer plant

Custom-Made Wire Harness: How to Build a Wire Harness?

Making a wiring harness includes the following steps.

Step:1 Design

Firstly, you need to pick a plan to make a wiring harness. Whether you hide a wiring harness in a glove box of an automobile or the back panel of your refrigerator, the wiring harness must have a custom design that suits the electronic part of the product. At the same time, engineers also decide on harness components and other specifications.

Step:2 Prototyping

Engineers prepare a wire harness prototype and test it on a genuine version of the final product in this step. As a result of the prototype testing, you can identify any issues before the production runs and ensure optimal performance from the product.

Step: 3 Production and Assembly

  • Wire cutting: Technicians must cut the wires to the desired lengths through a wire-cutting machine.
  • Stripping and connections: They strip the wire ends to expose the cores. This step is essential to attach connector housing and terminals.
  • Assembly: Lastly, engineers assemble the harness on a workbench or assembly board to give it the desired designs.

Step: 4 Testing

Finally, after product completion, it is essential to check the wire assemblies for electrical safety so they are safe to use in real-life applications.

Custom-Made Wire Harness: Building a wire harness right

To build a wire harness correctly, you must consider the following.

Custom-Made Wire Harness: Harnesses layout and fixturing.

During wire harness manufacturing, it is a practice to develop mock-ups or form boards. As per NASA technical standard NASA-STD 8739.4, the form board specifies all the physical restraints that a cable or harness encounters during installation. For example, during fixturing, there are preformed harnesses with bends and offsets so they can fit into a location. During fixturing, straps, shielding, or lacing tape ensure that harnesses do not face any tension after installation. In the form board, the layout must have a design limiting the distortion, pulling, or bending of the wires during installation. Further, engineers can secure the harness breakout locations with straps and tapes.

For coaxial and fiber optic cables, NASA’s Best WORKMANSHIP PRACTICE defines the harness design so that these cables fall in the bundle’s center to limit bending and offer protection.

The maximum limit of the flexing and bending of a harness is the Minimum Bend radius, which can vary based on the wires and size, and harness construction. Further, the presence of coaxial or fiber optic cables also impacts the bend radius of the wires.

Custom-Made Wire Harness: Cable and harness protection

While wiring is not meant for humid environments, it must protect against moisture. According to NASA standards, manufacturers must install sleeves on all terminations. For improved seals, manufacturers must opt for heat shrink protection.

If using directly woven braids, it is essential to fit them properly to offer the required flexibility. Apart from this, NASA standard also recommends that if manufacturers use a pre-woven fabric braid, it should be loose so it can easily slide over the harness. They can secure the fabric sleeve through clamps, heat shrink, straps, and cable ties when required.

EMI protection

NASA-STD 8739.4 is vital to design harnesses to minimize EMI. In addition to the fabric sleeve, manufacturers also use metal braids. As it is essential to consider EMI during wire harness manufacturing for sensitive equipment, the metal braid protects the harness from Electromagnetic interference.

EMI shielding does not insulate completely from the cable. So, to keep the shield at the ground, manufacturers attach them to the connector shell with RFI or EMI back shell adapters. Further, they connect the cable shield terminations using heat shrink sleeves. Remember to keep the number of shields spliced to standard ground wire to four. Also, do not keep the grounding wire too long.

Custom cable assemblies Vs. Custom wiring harnesses

Industry professionals often use the words wiring harness and cable assemblies interchangeably. Both have some similarities in design and functioning but also some differences, which makes them suitable for different uses.

  • Firstly, the exterior sheath of a cable assembly comprises durable materials so they can bear heavy-duty applications. On the other hand, sheaths of wiring harnesses are not that durable.
  • Secondly, you can use a cable assembly for harsh moisture, heat, compression, abrasion, and friction environmental conditions. On the other hand, wiring harnesses involve minimum exposure to extreme conditions.
  • Lastly, you can get cable assemblies of different lengths having connectors at each end, while in wiring harnesses, you will find multiple connectors which can integrate with control panels.
Custom-Made Wire Harness: coils of electrical wires for installation

Image: coils of electrical wires for installation

Custom-Made Wire Harness: Custom wiring harness company

Cloom has stood at the forefront regarding the wire harness manufacturer for over a decade. We have a wide range of solutions for you in all applications. Since we have a  knowledgeable and expert team of technicians and engineers, we can surely help and streamline your production process.

Custom-Made Wire Harness: Wire harness manufacturing capabilities at Cloom

At Cloom, you can get custom wiring harnesses in any desired configuration. Our extensive manufacturing capabilities allow you to build a custom product based on your designs. Our engineers will work with you and test our products to ensure the correct performance. Also, we provide that your plans turn into fully functional custom wiring harnesses. We also add wire identification which eases the identification and installation process. You will also find serial numbers and date codes on our products. Our custom wiring harness designs include:

  • Unrestricted choice of wires, gauge, color, and insulation material
  • Any number of breakouts
  • Any number of wires
  • Custom connectors

Custom-Made Wire Harness: Product at Cloom

Off-Road and Engine harnesses:

  • Tested for shorts, opens, and continuity with Cirris test equipment
  • Marking of wires for circuit identification
  • Lengths of wire .500” to 1,000.’
  • Wire protection comprises over-braiding, molded grommets, or split loom
  • Simple to complex wiring harnesses for engines of Kubota, Caterpillar, Isuzu, Mitsubishi

Industrial controls and medical equipment harnesses

  • Mixed connectors are suitable for industrial controls and medical equipment.
  • Custom molded cable assembly
  • Multiconductor cable with discrete wire

Miniature wire terminations harness suitable for Industrial applications

  • Wire sizes of 32AWG
  • 0.5mm pitch connectors
  • Ideal for use in industrial controls and medical devices


Wiring harnesses are a low-cost solution for many industries to bundle and organize plenty of wires and cables. Industry experts can install wires and cables in different applications with their designs. Come to us if you also face difficulty managing wires and cables quickly in your products, contact us.