Whole Vehicle Wiring Harness Bundling and Fastening Design

Automotive Harness Wire Wrapping Design

Wrapping the wiring harness plays a role in wear resistance, flame retardancy, corrosion resistance, interference prevention, noise reduction, and beautifying the appearance. Generally, the following wrapping design plans are developed based on the working environment and space size.

The engine wiring harness works in a harsh environment, so a corrugated tube with high flame retardancy, waterproof and high mechanical strength is selected for wrapping.

The front cabin wiring works in a relatively poor environment. Most branches are also wrapped with good flame retardancy corrugated pipes, and some branches are wrapped with PVC pipes.

The instrument wiring has a relatively small working space and a relatively good environment, which can be wrapped with adhesive tape.

The door wiring and top line have a small working space and can be fully wrapped with tape. Some branches can be wrapped with industrial plastic cloth. The thinner top line can be directly attached to the body with sponge tape.

The chassis wiring has more contact with the body, so it is wrapped with corrugated pipes to prevent the wiring harness pins from wearing out.

Performance Analysis of Raw Materials for Wrapping Automotive Harness Wires

Corrugated tube

Corrugated tubes generally account for about 60% of wiring harness wrapping, and even more. Different from EV connectors, the main feature is good wear resistance, good high temperature resistance, flame retardancy, and heat resistance in high temperature areas. The temperature resistance of corrugated tubes is between -40-150℃. Its material is generally divided into PP and PA2. The PA material is superior to the PP material in flame retardancy and wear resistance, but the PP material is stronger than the PA material in bending fatigue resistance.

PVC pipe

The function of PVC pipe is similar to that of corrugated tubes. PVC pipe has good flexibility and bending deformation resistance. Moreover, PVC pipe is generally closed, so PVC pipe is mainly used for the branches of automotive harness wires at the bending corners to make the wire transition smooth. The heat resistance temperature of PVC pipe is not high, generally below 80℃.

Adhesive tape

Adhesive tape plays a role in bundling, wear resistance, insulation, flame retardancy, noise reduction, marking, etc. in wiring harnesses, and generally accounts for about 30% of wrapping materials.

The adhesive tapes for wire harnesses are generally divided into three types: PVC tape, woolen fabric tape, and cloth-based tape. PVC tape has good wear resistance and flame retardancy, and its temperature resistance is about 80℃. Its noise reduction effect is not good, and the price is relatively cheap.

The materials of woolen fabric tape and cloth-based tape are PET. Woolen fabric tape has the best wrapping and noise reduction properties, and its heat resistance is about 105℃. The cloth-based tape has the best wear resistance and its heat resistance is the highest, about 150℃. A common disadvantage of woolen fabric tape and cloth-based tape is poor flame retardancy and high price.

Fixing Design for Automotive Harness Wires

The central electrical box is generally fixed with steel strips, bolts, or directly installed on the body with the fixed structure designed by the electrical box itself.

Each wiring harness is generally fixed in the body hole with plastic cable ties, buckles, etc. The body holes are mostly circular or elliptical, generally with diameters of 5mm, 6mm, and 7mm.

The protective sleeves that are connected between each wiring harness are generally fixed collectively with a protective sleeve bracket and installed on the body.