1.5 Million Kilometers Later

High-voltage (HV) cables need to deliver reliable power across the gangway in electric buses, while maintaining adequate electromagnetic shielding. (Huber+Suhner)

June 15, 2026

The deployment of modern electric articulated buses continues to grow exponentially across the globe.

Capable of carrying approximately 50% more passengers than standard buses, these electric vehicles (EVs) are instantly recognizable by the flexible joint that connects the two sections of the vehicle.

To the untrained eye, this bend may first appear as a simple passage for commuters. The truth is that it’s a critical mechanical and electrical link. Known as the gangway, it’s essential that this flexible joint is weather-resistant and capable of withstanding constant motion and mechanical stress during operations, especially when traversing dense urban environments.

For electric buses, this challenge only intensifies. Not only must high voltage (HV) cables deliver reliable power across the gangway, but they have to do so while maintaining adequate electromagnetic shielding. Preserving these while under continuous movement and harsh conditions has introduced a complex engineering problem manufacturers would have sooner avoided.

Overcoming key challenges

This was certainly the case for a leading German mobility solutions provider with which Huber+Suhner now holds a long-term relationship. For a major project within the region, the company had developed a specialized test rig which simulated real-world conditions and stresses on the bus joint. They then needed to identify a cabling partner capable of delivering solutions that would work optimally within these test conditions and meet the sophisticated demands of articulated EVs.

It was during this testing process that Huber+Suhner joined the project, able to supply high-performance HV cables designed for durability, flexibility and electromagnetic protection. However, the project wasn’t without its complexities.

Historically, no EV component had ever been designed to move with the bus joint, making the project a first-of-its-kind endeavor. This is because the design of the gangway generates several engineering challenges, with the components regularly subject to stress, abrasion, fluctuating temperatures, moisture and long-term wear throughout daily operations. When paired with the continuous twisting, bending and vibration of the joint, these conditions place unparalleled demand on the lifespan of any HV cable system.

It was also essential that no magnetic fields escape the gangway, otherwise they could interfere with onboard electronics, compromise passenger safety, and breach strict electromagnetic compatibility requirements. For any solution to be deemed fit to work within the project, Huber+Suhner had to provide an exceptionally durable, electromagnetic-compatible cable that would work efficiently within the test rig.

Built for extreme conditions

For the project, Huber+Suhner opted for the screened Radox 155 and Elastomer S cables, manufactured specifically for prolonged flexible and dynamic use. This decision was taken following the success of the cables on a rail project, given that rail applications often mirror the same harsh environments that articulated buses experience.

The Radox portfolio of cables offers high UV-resistance with a broad temperature range. (Huber+Suhner)

Both products belong to the Radox portfolio, a range of high-performance cables engineered for demanding transportation and industrial environments. Developed using proprietary electron-beam crosslinking technology, Radox cables were designed to offer resistance to heat, abrasion, chemicals, moisture and mechanical stress while remaining lightweight and highly flexible. In intense high-voltage applications, where long service life and operational safety are critical, durability and reliability are vital.

The 155 and Elastomer S cables are suitable for the harsh automotive environments the test rig would mimic, as they enable single-core, highly flexible constructions. By combining high UV-resistance with a broad temperature range, engineers suspected these cables would work optimally under high stress without requiring additional protections, such as corrugated tubing. This would be true not only for the rig, but for when the project was operational, too.

The solution’s insulated design also provides maximum protection for shielding braid against potential damage, perfectly suited for the electric buses at the focal point of the project. With this in mind, Huber+Suhner was confident that the solution could operate effectively despite the project’s unique mechanical demands.

1.5 million km of cable endurance

The performance of the screened Radox cables was validated to the highest level during the testing phase. When routed across the joint within the specially designed mounting loop, the solution demonstrated the highest level of mechanical resistance among all cables evaluated by the customer. After passing the field test, the HV assemblies were fitted directly onto several bus ranges, further reducing overheads. The product’s mechanical strength and resistance ensured the gangway operated without additional protective systems or frequent component replacements, helping to simplify vehicle integration.

This was particularly timely given the procurement problems experienced by the customer. The previous cables used in EVs had proven to be weak and easily breakable, resulting in the depletion of a key passenger transport fleet. It was this situation which led to the development of the test rig, and the search for a new partner.

Success with this project has been proven through longevity. The cables supplied to the customer are still functioning to the highest level since their initial implementation in 2018, accumulating a combined 1.5 million km in miles traveled over the years. The mechanical strength of the solution has resulted in the entire transport fleet experiencing no operational failures since the partnership was solidified.

Connecting today and beyond

Ultimately, the project demonstrated how advanced cable technology can overcome one of the most demanding challenges in electric mobility: delivering reliable high-voltage power through a continuously moving bus joint. Both the screened 155 and Elastomer S cables were selected specifically for their combination of flexibility, durability and electromagnetic shielding, characteristics essential for maintaining safe and uninterrupted power across the gangway.

Jonathan Kaegi is product manager of automotive at Huber+Suhner. (Huber+Suhner)

The use of Huber+Suhner’s electron-beam crosslinking technology proved particularly valuable, enabling the cables to withstand harsh operating conditions like vibrations and extreme temperatures without compromising long-term reliability. This combination of performance characteristics made the technology especially suited to articulated EV buses, where both safety and uninterrupted power transmission are critical.

The assembly continues to perform to the same standard within the gangway to this day. The sheer mechanical strength of the solution has cemented Radox at the forefront of connecting challenging and unique EVs such as articulated buses.

Looking ahead, the cable strength offered by screened Radox cables will be used across even more sectors, complementing the enhancements Huber+Suhner already provides for trains, trucks and other vehicles.

Jonathan Kaegi is product manager of automotive at Huber+Suhner and wrote this article for SAE Media.