Tips for Making a Safe and Durable Wire Harness

When it comes to safe and efficient installation of automotive wire harnesses, three key tasks can make a big difference: Labeling, securing, and protecting the wiring. Completing these tasks helps prevent potential wiring errors and problems down the road such as electrical shorts, system failures, and potentially even fires. Here are some pointers.

Wire Identification

Identifying the purpose and function of each wire helps to ensure that the wires are connected correctly and that the harness is functioning properly. Labeling also helps with future troubleshooting and maintenance, allowing technicians to easily identify wires that need to be replaced or repaired.

Coloring and striping of wires can serve as an efficient way to label them. Each color or pattern indicates the wire’s function, such as “Ignition” or “Ground.” You’ll need to make sure that your staff knows what each color or pattern represents.

An even more reliable method is to have the actual words (Ignition, Ground, etc.) printed clearly on the wire jacket. The words can be applied in recurring intervals along the entire length of the wire, eliminating the need for technicians to try to follow a wire all the way back to its destination.

Waytek offers custom striping and printing services for many types and lengths of automotive wire and cable.

Securing Wires for Longevity and Safety

Properly secured wiring helps to ensure the longevity and safety of the wire harness, preventing disconnections and damage.

The most common methods of securing wiring are using cable ties, clamps, and electrical tape. Cable ties are ideal for tying wiring together in bundles, while clamps are typically used to secure individual wires.

Electrical tapes come in a variety of specifications and strengths. The leading electrical tapes from 3M and tesa can be counted on to withstand the demanding environmental conditions of automotive use.  For tips on using tape effectively, see the article How to Wrap PVC Electrical Tape.  

Cable ties, clamps and tape should be used in conjunction with proper wire routing techniques to ensure that the wires are secure and properly protected. Route wires away from moving parts, sharp edges, and hot engine components. Use properly sized and rated connectors. And make sure to leave some slack in the wiring to avoid excessive strain or stress.

Protecting Wires from Potential Hazards

There are many products in the marketplace designed to cover and protect wiring. Among the most common are heat shrink material, which is used to protect individual wires, and split loom tubing, which is used to protect multiple wires bundled together. You can learn more about selecting and using heat shrink in the Waytek article Heat Shrink 101.

Another popular wire covering is braided sleeving. Expandable braided sleeving such as Flexo® PET by Techflex is especially user-friendly because it can be temporarily removed to allow for wire maintenance or repair. This “self-closing” sleeving be opened by hand and will contract snugly back into place when returned to position over the wiring.

Right: Flexo® PET braided sleeving from Techflex.

Other ways to protect wire include using cable breakout boots, liquid-tight strain reliefs, conduit, grommets, plugs and bushings. See the Waytek website for a full listing of the many types of wire coverings that are available. Applying a proper combination of wire protection methods will help keep your wiring safe from potential hazards such as abrasion, moisture, friction, and vibration.

A Note on Wire Quality

The quality of wire used in the harness also plays a vital role in safety and durability. Be sure you are using wire that is constructed from high-quality copper with durable jacketing to resist wear and corrosion. Avoid tinned or dipped aluminum wire, which is less conductive and more prone to corrosion.

For wiring that is used to transmit signals, such as CAN Bus cable, consider using shielded varieties that are designed to prevent interference from other wires.

Conclusion

By properly securing, labeling, and protecting the wiring in automotive wiring harnesses, you will ensure a safe and efficient installation, help keep the wiring secure and protected during vehicle operation, and make it easier to repair and maintain the vehicle’s electrical systems and components. These techniques, when combined with the use of high-quality wiring, contribute to a well-organized, durable wire harness.