4 Drawbacks of conventional wiring harnesses and how ...

DISCLAIMER: The views and opinions in the piece below are my own.

Read more

Here&#;s a quick look at how today&#;s wiring harness looks like.

Why does a wiring harness look this way? A part of that answer lies in understanding how today&#;s architecture has evolved over the last 50 years. As the electrical systems became more distributed, wiring harnesses also evolved to keep up.

This intricate network of wires, connectors, terminals, grommets, junction boxes, relay boxes, protectors are designed and assembled to carry amperes of current and gigabytes of data. However, they do come with some hiccups time to time.

The hiccups

1. Corrosion: This is a real problem, and probably why there are multiple DIY how-to guides on how to clean and manage corrosion in a wiring harness and articles explaining why WD-40 is your best friend. An integral part of a wiring harness are electrical contacts made of metal. And long exposure to moisture and other substances in the environment can lead to corrosion. Corrosion has two unwanted effects. It makes the contact mechanically weaker. Secondly, it increases the resistance of the electrical contact. And increased resistance can change the electrical characteristics, and could lead to faulty sensor output or just messed up data transfer within the vehicle. Recall of vehicles due to corrosion are not uncommon see this or this.
2. Joints: Most of the modern wiring harnesses are point to point, which means that there are no midway wiring joints. Midway wiring joints are not desirable because it creates a point of failure. Nowadays, manufacturers use more custom designed junction boxes which makes it a lot easier to manage all the joints and splits in the harness. And junction boxes really on more durable forms of contact like fastening and sometimes even welded contacts.
3. Weight: A typical wiring harness weighs about 30-50kg spanning kilometers when stretched out. The bulk of it comes from the metal conductors itself, followed by insulating cover and mounting solutions.
4. Manufacturability: Even today, manufacturing the harness for one vehicle take at least 10 different physical handovers. Simply because of the custom nature of a wiring harness and the differences in the harness with each different model and sub-variant of the vehicle. There are processes within this that have already been automated, like cutting, creating twisted pairs etc. But some processes are still semi-automated, which means you still need an operator for the machine. End-to-end automation for manufacturing wiring harnesses is quite far away with the current state of design. There is definitely potential here from designing from scratch, given the kind of technology we have now available to us.

Source: Bloomberg

What&#;s the whole point of wiring?

But the goal of a wiring harness(the physical part of the electrical system) boil down to 2 main aspects

1. Transferring electrical power
2. Data Connectivity

Electrical Power

Let&#;s do a quick thought exercise. If we could start from scratch, what would be efficient ways in which electrical power spread within the vehicle? Well, that is a trick question. The best actual way to transfer power is to not have to transfer at all.

Phantom feed, low energy, built-in powering are the next best options we have. A trend that is common now is having more functionality abstracted within SW. By having more powerful ECU&#;s, the overall number of ECU&#;s are dropping, as more and more functionality can be handled within the same ECU. The E/E architectures are centralizing to a small number of domain controllers and have fewer, low powered units within a small part of the vehicle, each governed by its own domain controller.

The next best thing could be if the sources of energy were distributed. And that would mean, different ECUs would have a battery within each piece of hardware. But that won&#;t solve any problem, as we would need to have a means of charging and maintaining them. Another key aspect is that OEMs assemble an array of ECUs from a range of suppliers.

But these are not applicable for all use cases. Here are a few factors to account for:

• Current requirement correlates to gauge size.
• Material and Length correlates to voltage drop.
• Transients, EMC, Antenna&#;s
• Fusing concept and the distribution of consumers.
• Single power source or distributed?
• High voltage systems to accommodate electric traction systems

Data Connectivity

The bulk of communication in today&#;s cars are done via CAN. A vehicle bus standard developed in the late &#;s that have been adopted as an industry norm. But CAN has issues of limited topology options, bandwidth etc. And now we are shifting to new solutions like ethernet. But how do you choose what the next industry baseline should be?

Here&#;s an idea: If you have a high enough bandwidth, you can send all kinds of data on the same physical layer. Sounds familiar? Well that&#;s because it&#;s what's happening in the consumer tech world with the USB-C revolution. In addition to that, recently the EU has ruled that all future devices shall have USB-C as the main charging interface. The hard part, similar to smartphone industry, is to get a standard adopted by OEMs, Tier 1, Tier 2 etc. within a common time frame. The standards and technologies are moving too fast, that neither OEMs or even consumers for that matter want to make any long term guesses.

Not only the Physical Layer needs to be harmonized, but the connector system as well. Otherwise, we still end up in the whole USB connector fiasco that we are familiar in the smartphone world.

H-MTD, which stands for High-Speed Modular Twisted-Pair Data is an emerging connector system which is capable of transferring up to 56Gbit/sec. It has proven to have desirable EMI properties and connector manufacturers like Rosenberger have developed connectors for this PHY also with optimum mounting forces.

Another fundamental optimization is if we could efficiently transfer power and data on the same PHY. Phantom power is more common within the audio world. There exists several IEEE standards specify transferring power along with data on a twisted part cable, collectively called Power over Ethernet.

A big part of the future is more and more wireless solutions within the vehicle. The tech stack have features now that are reliable, short range, built-in security features. However it comes with a different set of failure modes. Issues like interference could become a thing. Ex: Wireless opportunities, NFC, BT, WiFi. Harmonization among these standards and frequency bands is still a necessity for a more wide spread adoption within the industry.

Consolidated Electronic Wire & Cable can assemble a variety of such harnesses, and our experts can help you determine what will fit your needs. However, if your needs are especially complex or specific, we also offer custom harnesses.

Custom Wire Harnesses

Wires and cables are indispensable tools for a wide range of today&#;s home and industrial systems, and harnesses allow technicians to create orderly, carefully fitted wiring solutions for any type of environment. Depending on the specific needs of an application, these harnesses can be built to accommodate systems up to 600 volts (UL) or volts (military), with high performance at temperatures ranging from -65 °C (-85 °F) to 250 °C (482 °F).

When evaluating a new cable or wire harness solution, remember to carefully consider the specific environment it will be used in and the temperature and conditions it will be exposed to. Evaluate all of the different cable types you may be able to use; custom wire and cable harnesses can be crafted with nearly limitless style and material options, including:

• Wire ties
• Lacing
• Insulation materials of all kinds
• Custom colors
• Heat-shrink coatings
• Custom labeling or barcoding
• Four-color ink stamping
• Individual tagging
• Independent circuit IDs
• Polypropylene, nylon, and paper fillers
• Custom shielding

We take a strategic engineering approach to select the most ideal shielding and connectors for your application. At the same time, we take into account all applicable regulatory standards to ensure that your final harness is safe, reliable, compliant, and effective.

Other factors that bear on harness design include:

• Whether the harness will be exposed to continuous flexion

• If the harness will be used indoors or outdoors, and under what specific conditions

  If you are looking for more details, kindly visit Suntex Electronics.

• How many circuits and conductors are required for the assembly, as well as their characteristics

• Level of voltage to be carried

• Potential exposures, including chemicals, corrosive fluids, weather conditions, and moisture from other sources

• Maximum, minimum, and average operating temperatures, as well as potential fluctuations

• Local safety and environmental regulations that might impact component selection, installation, and inspection

• Routing, breakouts, general shape of form

 

Wire Harness Applications

Since wire harnesses can be used to solve such a diverse range of interconnection challenges, they are used extensively throughout myriad industries. Virtually any industry that relies on cable arrangements can benefit from the use of wire harnesses. The following sectors, among others, often rely on wire harnesses to maximize efficiency and protect employees against the dangers of haphazard wiring:

• Aerospace.

  Wire assemblies are used in an expansive range of aerospace products, such as drones, satellites, and aircraft to facilitate the transmission of power, communication, and more.

• Automotive.

  Wire harnesses are critical for saving valuable space within automobiles within the dashboard, under the hood, lighting/signals, and more. They are also important for organizing complex wiring in such a way that technicians can easily identify their purpose.

• Medical

  . Hospitals and clinics rely on wire harnesses to organize and protect wires in and between equipment, including crash carts, diagnostic and imaging equipment, dental equipment and more.

• Telecommunications

  . Wire harnesses optimize use of space in a variety of telecommunications equipment, such as modems, routers, repeaters, and a variety of other communication and broadband equipment.

• Information technology

  . Nearly all computers, laptops, servers, and other IT technology contain wire harnesses to optimize space and organize wires for easy identification and installation by technicians.

• Construction

  . Wire harnesses are widely used within structures to provide wiring insulation and organization.

• Manufacturing

  . CNC machines and other powered manufacturing equipment rely on wire harnesses to route and organize external and internal wiring.

• Robotics and automation

  . Wire harnesses are used on most automated equipment and robotics to safely route, group, and protect critical wiring

Benefits of Wire Harnesses

Wire harnesses would not be so widely used if they didn&#;t present substantial benefits for wiring applications. Among other advantages, wiring harnesses benefit companies in the following ways:

• Decreases cost compared to multiple individual assemblies

• Improves organization, especially when a system relies on hundreds of feet of complicated wiring

• Decreases installation time for projects involving extensive networks of wiring or cabling

• Protects conductors from the elements outdoors or from chemical and moisture exposure indoors

• Provides a safer work environment by cleaning up loose or scattered wires, maximizing space, and preventing trips and damage to wires and cable

• Enhances safety by minimizing the risk of shorts or electrical fires

• Decreases installation and maintenance time by potentially minimizing the number of connections and organizing components in a logical configuration

The many benefits of wire harnesses stem from very simple design principles. Sheathes protect wires against abrasion or exposure to hazards, minimizing the risk of workplace incidents. Connectors, clips, lacing, and other organizational strategies drastically reduce the amount of space that wiring must occupy and ensure that technicians can easily locate the components that they need. For equipment or vehicles that regularly contend with a web of lengthy wires, a wire harness is sure to benefit everyone.

High-Performance Materials

In addition to ensuring optimal organization, a high-quality wire and cable harness will provide reliable insulation and protection for the conductors within. There are many options for durable harness materials, and it&#;s important to select what is most beneficial for your needs.

Some of the most common insulator materials include:

• PVC, or polyvinyl chloride
• SR-PVC, or semi-rigid polyvinyl chloride
• Cellular polyethylene
• EPDM, or ethylene propylene diene monomer
• TPE/TPR, thermoplastic elastomers
• PE, or polyethylene
• Both low- and high-density polyethylene (LPDE and HDPE)
• Cellular, or foam, polyethylene
• PU, or polyurethane, as well as polyurethane and nylon blends
• Low-smoke plenum copolymers
• Polypropylene (PP) and cellular (foam) polypropylene
• FEP, or fluorinated ethylene propylene
• TFE, or tetrafluoroethylene
• PTFE, or polytetrafluoroethylene
• ETFE Tefzel
• PVDF Kynar
• ECTFE Halar
• IRR/PVC, or irradiated polyvinyl chloride
• XLPE, or cross-linked polyethylene
• Vinyl

In choosing between these and other options, it&#;s important to take into account environmental variables such as operating temperature and moisture. The presence of moisture, for instance, can necessitate a water-resistant material like polyethylene to avoid damage to the conductors.

Cable & Wire Harness Solutions

At Consolidated, we&#;ve been helping clients develop these solutions for more than 100 years. Our custom harnesses and assemblies can be found in a wide range of applications, and all projects are supported by our state-of-the-art production facilities.

Bearing in mind relevant industry standards and specifications such as IPC/WHMA-A-620, there are countless ways to develop a harness or assembly to meet the needs of a particular project. And with various options available for shielding, fillers, materials, identification, and style, the most efficient organizational solution for your project is simply a matter of strategic engineering.

Our current catalog includes a wide variety of robust, high-performance cable and wiring harnesses guaranteed to organize multi-wire systems across industries. Our custom harness services are tailored to each and every client, with our technicians drawing on decades of multidisciplinary experience to determine the ideal strategy for each operation. Whether your cabling is for a home appliance or a state-of-the-art aircraft, our assemblies can enhance organization and safety at a competitive price-point. 

To learn more about our custom wire and cable harness solutions and discuss how we can help with your next project, check out our comprehensive eBook, &#;Creating a Custom Cable,&#; or get in touch with our team today.

Contact us to discuss your requirements of Wire Harness Supplier. Our experienced sales team can help you identify the options that best suit your needs.