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Apr 26, 2021


Don’t Let Your Cables Be the Weakest Link

From the front of the tractor, all the way to the back of the trailer, there are air and electrical lines that control the pneumatic brake system and the electricity needed to power the lights and other auxiliary applications on the trailer, such as liftgates.

However, a tractor was designed to pull its load behind itself with the ability to drop off the trailer, chassis, or flatbed at a docking bay or yard for loading and unloading purposes. Caught in the middle of this disconnect are the cables that link the tractor and trailer’s air and electrical lines together, similar to how an extension cord functions for home use. Protecting these cables from damage, whether the truck is pulling a load or not, is very important for many reasons.

Performance as the Weakest Link

Damaged electrical cables ultimately result in low voltage drop stemming from one of two circumstances. One being prolonged routine stress in vulnerable areas of the cable, particularly at the back of the trailer-side plug, or two, water and contaminants that have found an entry point through the plug or damaged jacketing, wicking corrosion through the electrical system and blocking the flow of electricity. As one would imagine, this can lead to flickering or inoperable lights, which is one of the number one reasons for a citation. Additionally, in the worst-case scenario, it could cause a collision with another driver. And even if the damage was found before any of these situations occurred, it still results in unscheduled downtime.

Air lines are susceptible to the fall-out of damage as well. Typically, a driver will be cited at a weight station during DOT inspection for the cosmetics of damage before lines have the potential to burst. Kinked nylon coils with white marring discoloration are considered a possible blockage for airflow and chaffing, nicks, and cuts can lead to loss of air pressure. Without functioning air lines, the trailer will lose the operation of its brakes. But again, no matter the situation, it all results in unexpected downtime. 

Building the Strongest Link


Spec’ing quality cables that are designed to hold up in extreme conditions and take a beating on their own with features such as quality jacketing and connectors is a good first step. Electrical cables with UV protection and excellent abrasion resistance and cable guards and sealed or molded weather-proof plugs are features with cable protection in mind. Rubber air lines are considered more robust in their make-up than coiled air lines; however, there are coiled air lines on the market designed to perform in harsh weather conditions and prevent coil sag, such as Phillips POLAR AIR®. Spec’ing anodized gladhands will slow the degradation of the aluminum gladhand body.

Combination assemblies offer a unique take on cable protection. They combine straight rubber air lines and straight electrical cables into one protect unit combined in spiral wrap, avoiding tangles and providing abrasion protection.

Additionally, cable working length should always be considered. Typically, a 15-foot working length and coils with long leads will work in most standard use cases; however, keep in mind this is not necessarily the case for all applications.

Proper Installation and Cable Support

The next step is proper installation and keeping these products off the deck plate with quality cable support. 

The adapter fitting on the tractor side should always be replaced when installing new air lines, and gladhands should also be replaced simultaneously. The plugs on the electrical connections should always be locked into place, with the latch key catching on the socket lid.

Depending on the cable application, coiled or straight, cable support springs should be installed to allow maximum use of the cable working length. A single spring is needed to support coiled cables with the hose holder placed near the base of the first tractor-side coil, rather than the middle of the coils. With straight applications, two springs should be used, one as the support spring, and the other as the working spring, with the straight or combination assembly cables wrapped in one large helix that expands and contracts just as the coils would on a coiled air line.

When the tractor is disconnected from the trailer, cables should be stored away in a back-of-cab stowage system to protect the plug ends and gladhands from damage and keep cables from laying on the deck plate. Disconnected cables should never be zip-tied to the deck plate.

How to Maintain the Strongest Link

The last to follow is routine maintenance. Nothing is indestructible. Without proper care, even the best products can fall into disrepair. It is imperative that drivers perform their walk-through regularly and that scheduled routine maintenance ensures cables are well supported and in good working order. This includes their connections. Electrical plugs and sockets should be cleaned and greased. Cables can be tested for continuity to ensure all circuits are in working order. Gladhands should be inspected for seal replacement, loose detent and connector plates, and even signs of corrosion. Any issues found should be addressed immediately, either with repair or replacement.

By spec’ing, properly installing, and maintaining the cables that link the tractor to the trailer, you can ensure an uninterrupted ride and avoid the pitfalls that lead to downtime with the strongest link possible for your set-up.