VW 80135 Electrically Conductive Threaded Connectors - Grounding Connectors

The “VW 80135 Electrically conductive threaded connections - Grounding connections” standard, developed by the Volkswagen automotive company, describes the requirements for electrically conductive threaded grounding connections for DC electrical systems with electrical system voltages up to 48 Volts in motor vehicles.

The basic requirements in this standard are defined as follows:

• Design: The design must be based on the drawing or drawing and master data list and the product description manual. The requirements in these documents take precedence over this standard. In case of deviations from this standard, the mechanical and electrical functions of the grounding connection must be verified and documented by tests.
• Environmental compliance: Must comply with the “VW 91100 Environmental standard for vehicles - Vehicle parts, materials, fuels, coolants, fluids and lubricants, original parts, replacement parts, economy parts” standard.

The requirements for grounding threaded connections are defined in this standard as follows:

• General requirements:
• According to VW 01029 standard, the space required for access with crimping tools must be taken into account.
• Electrically operated geared connections must be designed according to the VW 01110-1 standard, tested for electrical connection characteristics, and designed for the relevant service life. The VW 01110-4 standard should be used for verification and release purposes.
• A failure modes and effects analysis should be performed for each deviating gear electrical connection.
• The grounding connection must not be fitted to adhesive-joined, riveted, or studded white components without prior verification and documentation of the grounding connection's effectiveness; otherwise, the required electrical conductivity cannot be ensured.
• For infotainment system grounding connections, there must be a minimum distance of 100 mm from other types of grounding connections.
• A thin gasket with a radius of 40 mm should not be applied. Contamination (e.g., wax, oil) on contact surfaces and threads is prohibited. Appropriate protective measures must be taken.
• It should be possible to reattach the components after use.
• Grounding studs to be used:
• For grounding connections to steel sheet body components, it is preferable to use the grounding studs specified in the table entitled “Steel grounding studs - Individual parts and assemblies”.
• Grounding threaded connections to aluminum sheet housing components must be made with metric threaded bolts. Particular attention should be paid to the surface material combination. Grounding threaded connections via aluminum contact elements and standard, multi-purpose, or mass-produced parts are applied with M6 to M10 thread sizes. The table entitled "Aluminum contact element assembly and aluminum grounding stud assembly" should be followed in this regard. Housing contact elements must have threaded blind holes. For threaded blind holes in aluminum contact elements, the permitted bolt length increases according to VW 60361 standard must be observed. It is forbidden to fix cable lugs under an aluminum or aluminum alloy reinforcement terminal nut.

In the complex world of automotive engineering, where precision meets innovation, standards like VW 80135 play a crucial role in ensuring reliability and safety. This comprehensive technical specification regulates how electrical grounding and conductivity are provided in vehicles via threaded connectors. As electric vehicles and hybrid systems become more widespread, understanding the VW 80135 standard is vital for engineers, manufacturers, and enthusiasts.

Volkswagen has long emphasized stringent standards to maintain quality across its global supply chain. The VW 80135 standard emerged during the automotive industry's transition to electrification: a period when providing low-resistance electrical paths necessary for grounding, electromagnetic interference (EMI) protection, and corrosion prevention in vehicles became increasingly challenging. Traditional bolted connections often failed under vibration, thermal cycling, or environmental exposure, leading to intermittent conductivity problems. The VW 80135 standard addresses this issue by defining materials, designs, and test protocols for threaded connections that maintain electrical integrity throughout a vehicle's lifespan. With electric vehicles dominating sales, recent updates to this standard also incorporate lessons learned from high-voltage battery systems and autonomous driving sensors. The latest versions emphasize sustainability by mandating the use of recyclable materials wherever possible.

The VW 80135 standard essentially defines threaded connections as electrically conductive if they achieve a contact resistance lower than 2,5 milliohms under specified conditions. The basic requirements of this standard are as follows:

• Material selection:
• Base metals: Iron alloys (e.g., low-carbon steel) with a minimum IACS (international annealed copper standard) conductivity of 10 percent must be used in the connections. Non-ferrous options such as aluminum are permitted, but require protective coatings.
• Coatings: Zinc coating (minimum 5-8 microns) or nickel substrates are standard for corrosion control. The specification prefers trivalent alternatives, prohibiting chromate-converted coatings due to environmental concerns.
• Prohibited elements: High-sulfur steels (greater than 0,035%) are prohibited because they promote galvanic corrosion in humid environments.
• Design and geometry:
• Thread profiles: Metric ISO threads (e.g., M6 - M12) with a thread and tolerance in the 6 g/6 h class. Helical inserts or locking features must not impede conductivity.
• Contact surfaces: At least 60% of the bearing surface must be free of lubricant or insulator. Torque specifications range from 10 Nm for M6 bolts to 120 Nm for M12 bolts and are calibrated to provide 20-30% thread engagement.
• Stacking considerations: Paint peeling or conductive shims must be taken into account at joints in multi-layered assemblies (e.g., body-chassis).
• Test protocols: The VW 80135 standard mandates a multi-stage verification process:
• First resistance test: Measured at a 1 kN preload using the four-wire Kelvin method.
• Environmental cycle: 1.000 hours of salt spray (ASTM B117), thermal shock (-40 degrees to 125 degrees), and vibration (ISO 16750-3) to simulate 10 years of service.
• Aging simulation: Includes microvolt drop measurements after corrosion to verify less than 5% deterioration.

Failure in any test results in rejection, requiring traceability through batch coding. This rigor ensures that the links perform well across every vehicle.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its customers, providing the advanced testing services they require, and assisting in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the "VW 80135 Electrical conductor threaded connections - Grounding connections" standard.