Wiring harnesses come with coverings or auto wire harness tape, which securely bundle and protect them from high temperatures and harsh weather conditions.
However, every harness needs different types of coverings having different properties and characteristics.
Today, we are going to have a clear picture of the auto wire harness tape.
Table of Contents
- Applications of auto-wiring harness tape:
- How can you choose a good quality auto-wiring tape?
- A guide for wrapping tape on wire and cable harnesses:
Applications of auto-wiring harness tape:
Wire harnesses have a complex design and perform various sensitive functions. Thus, they require tape applications in a precise manner.
While automotive manufacturing has become automated in many senses, tape application to the harnesses is still a manually done job.
Mainly applied in the engine compartment and interior cars, the harness tape may vary from vehicle to vehicle.
Also, the choice of adhesives on the tape depends on the location of the tape and the conditions which it will go through.
For instance, engine compartment harnesses need tapes that are resistant to temperature.
On the other hand, harnesses within the car may require tape to mitigate noise.
You need flexibility and abrasion resistance in both the above cases of harness tape.
Applications of auto-wiring harness tape
How can you choose a good quality auto-wiring tape?
Tapes that wrap around wires in a harness must withstand chemical exposure, hot and cold temperatures, and abrasion from roads or rocks.
A good quality auto wire harness tape undergoes all these conditions while adhering to its place.
Here are a few features you must look at while selecting a tape for auto harnesses:
Tight wrapping tape:
The most widely used wire harness tape is PVC or polyvinyl chloride.
This flexible plastic tape allows tight and firm wrapping around the wires, which need to navigate in the tight spaces.
Wire harness tapes come in ratings from A to F based on their abrasion-resisting capacity.
Here, A indicates no resistance, while F indicates extremely high abrasion resistance.
Based on ISO 6722, the tapes undergo a scrape abrasion test to get a specified rating.
For this, technicians rub an abrading tool on the tape under defined temperature and pressure conditions.
Class A tape can withstand less than a hundred strokes only, while Class F can bear more than 15,000 strokes before failing.
As an abrasion-resistant solution, cloth polyester tape is quite prominent due to its resistance to abrasion and heat.
Also, it is very flexible and tearable with hands, making manual application easy and quick.
Further, a non-woven polyester is good for noise reduction applications.
Various other tough textiles have been used instead of standard PVC tapes.
Insulation from heat and electricity:
Auto wire harness tape must be a heat and electrical insulator, and again, PVC comes as a good option.
However, as the engine compartment has high temperatures, automakers also look for other options like vinyl, foil, and polyester.
Further, glass cloth tapes are also a better option than textile harness tape.
For insulation and heat resistance, you must look for the right adhesive layer apart from the tape backing. A good quality adhesive layer remains stuck to wire bundles even in extreme temperature fluctuations.
Resistance to chemicals and contaminants:
Woven tapes are the best if you expect oil and contaminants in any application because they are treated or laminated.
However, it is best to use foil and smooth polymers. Some polymers like PVC and polyester can protect the harness from corrosive substances.
If you pick a cloth tape, it is good to back it with flame-retardant, chemical-repellent, and waterproof material.
Interior car wiring harness
A guide for wrapping tape on wire and cable harnesses:
Here, we will explain the method suitable for all materials, which can be wound around the cable or a wire bundle in a spiral manner.
The methods mentioned here are just for an idea and are not a rigid requirement.
We have received good electrical and mechanical performance based on the experiments and procedures mentioned here.
However, Cloom does not guarantee any end-performance results.
Choose the type of tape used:
The tape installation procedure depends on which type of tape you are using.
Are you using woven fabric tape, adhesive-backer, metal foil, or an elastic polymer film?
Will it hold all the wires loose enough to allow their movement in a direction, or do you need to hold wires together tightly in a small bundle?
Some tapes also give extra performance features like improved dielectric insulation, abrasion protection, high thermal protection, and EMI shielding.
Once you know the intended use of the tape, you can find out how much coverage and layers you require.
Also, you will be able to figure out the installation technique precisely.
How much tape do you need for your project?
This question has no fixed answer, as all installations and tape materials differ.
But, if you are using thermal and EMI materials, you will need high coverage for better performance.
Here is a table roughly describing the length of tape required for a linear foot of cable.
These values are calculated considering 50% overlap, straight run, and with material thickness as zero.
|Tape width in inches||Tape winds per foot of cable||Cable diameter (in inches)|
If wrapping tape involves bending, you may require more tape than mentioned for one foot of the cable.
So, a good thumb rule says to add ⅓ of the foot/length to the mentioned length of the linear tape in the table.
Also, don’t use wide tape for covering the area to minimize the length of tape required.
As the diameter increases, wrinkles and open gaps also increase during tape applications, defeating the ultimate purpose of the tape. Also, it won’t look good aesthetically.
Tapes come with an adhesive backing to hold them on the wire and to avoid slipping while you unwind them.
While some tapes have this adhesive part exposed as you unwind, others come with a thin paper release liner, which prevents adhesive from sticking to the roll.
On the other hand, a few tapes do not use adhesives, for example, my self-vulcanizing and fabric friction tape.
Except for a few, most tapes keep the adhesive face towards the cable or wire bundle. For tapes that come with a paper-release liner, remove it before applying it around the cable.
During tape applications, always move in a spiral manner where wind the first tape at a 75-degree angle, moving towards the cable length. Make sure that with each round, you cover the previous wind up to 50%.
Polymer film tapes are pretty elastic, and thus, you can stretch them a little during winding to give a smooth and wrinkle-free look.
However, do not stretch them too much, as it will reduce the tape width. It may also cause individual coils to pull back, thus exposing the adhesive part over time.
Further, for metal foil and woven fabric tapes, you need to be extra careful as these tapes don’t have any elasticity.
You must also take the starting angle carefully so that individual tape unwinds smoothly and firmly with minimum wrinkles.
While installation, if you face breakouts, it is essential to back up. Wrap the tape on itself to move in the opposite direction.
However, it is always better to wrap the small breakouts first with a narrow tape.
Then, terminate this narrow tape a few inches before the main cable runs.
Once you cover all the breakout legs, take a wide tape and cover the main cable run.
If you are using EMI tapes, they must have at least a 3-4 inch overlap.
Also, for tape material with one conductive side, ensure that all conductive sides remain in contact with each other.
Grounding EMI tapes:
While installing EMI shield tapes, you must ground their one end for proper functioning.
You can take a ground pathway in different ways, depending on the requirements for EMI shielding and the material of the EMI shield tape.
Ensure that you contact experts to understand the ground termination requirements of any applications.
Tape applied to the engine wire harness
Though you can find tapes in various materials and even at affordable rates, the final installation cost goes high as the process is labor-intensive.
Further, the final finish of the tape wrapping depends on the installer as it requires experienced hands.
Thus, it is advisable to use tape wrapping only for short-length cables, cable branch legs, and cable intersections.
Use zip-on jackets or wrap-around materials for long cable runs to maximize wire harness assembly efficiency.
At Cloom, we use pre-engineered products and high-quality materials for securing wire harness assemblies to make them cost-effective and reliable. Contact us for custom solutions for device-laden modern vehicles.