VW 75205 Twisted and Stranded Cables - Requirements and Tests

The standard “VW 75205 Twisted and stranded cables - Requirements and tests”, developed by the Volkswagen automobile company, describes the requirements and test methods for twisted, unshielded low-voltage cables for the nominal voltage range ≤ 60 V.

Thin-walled cables with cable cross-sections ≤ 6 mm2 comply with the valid construction tables in accordance with standards VW 60306-1 (copper cables), VW 60306-2 (aluminum cables) and VW 60306-4 (copper alloy cables).

Usage examples:

• Transmission of digital and analog signals with high frequency (HF) requirements
• Minimization of interference emissions and connection sensitivity
• Cables for sensors, airbags, speakers, CAN and similar
• Packaging of single cores

The basic requirements in this standard are determined as follows:

• The tests must be carried out by an independent institute accredited according to the DIN EN ISO/IEC 17025 standard.
• Only cables made of the same base material, using the same laying direction and of the same temperature class published in standards VW 60306-1 (copper cables), VW 60306-2 (aluminum cables) and VW 60306-4 (copper alloy cables) may be used.
• Essentially, the two methods described in this standard can be used to produce cables conforming to this standard.

For the purposes of this standard,

• When no clear distinction is made between twisted and twisted, this standard uses the term twisted cable for both terms.
• Twisting: Bulk cable manufacturers use twisting machines to produce multicore cables with cable lengths from a few hundred meters to several kilometers. In common usage, the term twisting is used here for simplicity. Sheathed cables use only twisted goods.
• Low torsional twist with backward twisting: Back twisting during spinning ensures low torsional twist. After twisting, the twisted bundle retains its original relaxed form.
• Low-twist bending without back bending: These products are used for simple applications.
• Twisting: When a cable manufacturer twists a multi-core cable on a machine, this is usually done with pre-cut lengths of individual twisting elements, usually up to several metres, and with pre-installed contacts, usually without back-twisting. In common usage, the term twisted is used here for simplicity.
• Twisting without back-twisting, back-twisting: In this process, the bent elements need to be over-twisted due to back-twisting, which reduces the quality. The defined back-twisting in this process relieves the stress in the bent bundle.
• The twisting process also includes mechanical elements that enable the twisting elements to be individually wound backwards, thus supporting low-torsion laying.

The dimensions and construction of individual cables should be taken from the relevant sections of the appropriate annexes for the standards VW 60306-1 (copper cables), VW 60306-2 (aluminum cables) and VW 60306-4 (copper alloy cables). The dimensions and conductor construction of individual wire-free cores should also be taken from the standards mentioned above.

According to the VW 60306-1, VW 60306-2 and VW 60306-4 standards, materials for stranded cables must only be single-core materials with the same cable structure and from the same manufacturer.

Twisted pair cables must be produced on suitable machines. For this purpose, the supplier submits a document containing the necessary information for each machine type and production location to the relevant department.

The requirements for the production process are as follows:

• The quality and process requirements for twisted and stranded cables in accordance with Annex A of the standard must be observed.
• The types of machinery used must be documented in accordance with Annex A.
• The fold length must be observed along the entire length of the twisted cable in accordance with the drawing. Connectors with shorter fold lengths at the beginning and end of the cable are only permitted for cable cross-sections ≥ 0,35 mm2.
• Alternatively, the ends of the twisted cables can be secured, for example using adhesive tape as a binder.
• Product damage that impairs function during or after the bending process is not allowed.
• The appropriate drawing applies. Especially for special cables (e.g. CAN), attention should be paid to the length of the free ends and the shorter layer length.
• The allowable tolerances for layer length and cable offset (length offset of twisted single cores) must be observed.
• The cables must be manufactured with back twist according to the VW 60306-4 standard.

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