Manufacturer’s guide to custom cable


Custom cable: what you need to know

From industrial equipment to AgTech and consumer electronics, many of the products that shape commerce and daily life rely on cable assemblies to function. The fact is, engineers of all types must understand wiring and electricity to design, improve and manufacture products.

When your cable needs are straightforward, you can spec and source assemblies as simply as you source other standard materials and parts. But electronic functions continue to grow more complex, and many manufacturers need cables with unique specs or capabilities.

Custom cables allow manufacturers to engineer the electrical components of their part or product and use a cable assembly built to meet their needs to a T. But going from idea to product takes more than listing what you want and handing a spec sheet to procurement.

This guide covers what you need to know about:

  • Custom cable design 
  • Custom cable manufacturing 
  • Cable standards and regulations 
  • The custom cable supplier marketplace 
  • Where Multi-Tek fits in 

Custom cable design

When there’s no off-the shelf cable on the market that fits your needs, you need to design something custom. And getting it right is crucial. Your cable design will impact everything from cable performance and production cost to production timelines and manufacturing processes.

This shouldn’t intimidate you, though. Cable design can be quite simple, and custom cable suppliers make great resources if you run into any roadblocks.

custom cable design software

How to know you’re getting it right

When designing a custom cable, you’ll want to feel certain you’re making the right decisions. Sometimes what is right or wrong isn’t entirely clear. But the answers to these three questions should keep you on the right track and help guide your design process.

  1. What performance does my product need from its cable assembly?
  2. What restrictions does my product or application place on my cable?
  3. Can this be any more straightforward?

Put simply, make sure that the cable you design meets the needs of your product. If it doesn’t, it isn’t worth manufacturing. Your cable performance needs should inform the physical and electrical specs you design for.

Knowledge of your critical performance needs will help you identify areas where standard components will do. Specifying high performance components with tight tolerances for the sake of it makes manufacturing expensive and handicaps your supply chain. The best cable design perfectly suits your needs without sacrificing manufacturing efficiency. That saves you money and saves your supplier time.

Keep the above in mind, and you’ll make lots of good decisions during your cable design process.

What you’ll need to do

Once you’ve determined the performance you need from your cable, it’s time to start specifying components. A good rule of thumb is to start with specifying your conductor. Your conductor will determine the performance level of the cable — how much power it carries, the integrity of its signal, et cetera. And settling on a conductor gauge will help narrow down connector choices later.

Then you can specify your conductor’s insulation and shielding, if needed. Insulation protects your conductor from physical elements like heat, cold, light and chemicals. Shielding protects your cable from electromagnetic interference (EMI). Your insulation and shielding choices will impact other design characteristics like cable flexibility and overall diameter.

Once you’ve specified your conductor, insulation and shielding, you can turn your attention to connectors and terminals. These make connections within your cable assembly and link your cable assembly to your product. They need to play nice with your conductor and its protection as well as the product itself.

Click through for our complete guide to custom cable design.

Custom cable manufacturing

Since a cable is made up of wire, protection and connectors, the bulk of the manufacturing process revolves around connecting wires to terminals, or to other wires, or to other components like fans. Your custom cable supplier gathers all the components you’ve specified and goes to work on assembly.

You may be familiar with the process of building cables by hand with crimping tools and elbow grease. But advanced tooling allows for increased fidelity to design, quicker turnaround times and lower production costs.

Hand crimping vs. machine tooling

Most manufacturers who build their own custom cables in house do so by hand. That means manually cutting, stripping and crimping wires to terminals. The process is laborious and prone to inconsistencies, especially at production scale.

Specialized custom cable suppliers use advanced tooling to crimp connections faster, more consistently and more affordably. A benchtop crimp applicator makes perfect crimps of pre-cut wire simple, but a cut, strip, terminate (CST) machine goes a step further to cut wire, strip it and crimp it automatically, at high speed, even performing its own quality testing.

But fancy new equipment won’t turn bad practices to good practices if faulty connections persist in your production line. Without proper training, an applicator will only help you perform bad crimps faster.

Before upgrading your tooling, consider the training cost on new equipment and make sure you’re willing to develop expertise in house. Sometimes a more elegant solution is finding a right-fit cable manufacturing partner.

Click through for guides to hand crimping or advanced crimp tooling.

Wire splicing

Splicing connects two conductors to each other. While it’s common for engineers to specify soldered connections, specialized custom cable suppliers can use a number of tools to splice wire.

We typically steer people away from heat shrink splices and butt splices in manufacturing settings. Heat shrink splices are unreliable, and butt splices are laborious to produce without offering more reliability than typical soldered connections.

We use auto-splice machines where possible to produce reliable connections at low cost. In any case, once splicing wires, you should protect the connection with heat shrink and/or insulation.

Click through for a detailed comparison of wire splicing methods.

Wire harness manufacturing

Wire harnesses differ from cable assemblies in their layout, but that difference has critical implications when it comes to manufacturing processes, especially at scale. Wire harnesses are built on boards to ensure that they’re laid out for ease of installation.

This process requires lots of manual labor and makes automation of wire cutting, stripping and termination challenging. Specialized wire harness manufacturers often have at their disposal very different equipment meant to supplement manual processes, rather than replace them.

Click through for a thorough breakdown of the difference between cable assemblies and wire harnesses.

custom wire harness

Quality control

In many ways, custom cable quality control looks similar to most industrial quality control. Different suppliers have different tools and practices in place when it comes to version control and process documentation, and it’s important to make sure your supplier’s practices meet your own standards.

Testing the physical product, though, primarily comes down to testing the quality of connections and terminations. These connections allow the cable components to function properly, and bad connections produce the vast majority of cable failures.

At Multi-Tek, we test crimped connections in three different ways: pull force testing, crimp height testing and crimp force monitoring. Each testing method has its pros and cons, but we prefer crimp height testing and crimp force monitoring because they’re non-destructive. Since pull force testing is destructive, you can only use it in sample-based testing.

We go beyond sample-based testing to guarantee 100% cable functionality. If you can’t risk poor cable performance, consider prioritizing a cable supplier with strong quality control practices.

Click through for a guide to crimp quality testing.

Cable standards and regulations

What ISO standards are relevant?

The most relevant ISO standard for custom cable manufacturing is 9001, which pertains to quality management. Working with an ISO-certified supplier ensures that your cable is produced using generally accepted best manufacturing practices.

custom cable experts

IPC/WHMA-A-620 standards

IPC/WHMA-A-620 standards set out best practices particular to cable and wire harness manufacturing. They have standards for three different classes of product, based on how critical the cable’s performance is.

Most general consumer products adhere to Class 1 standards, where “the major requirement is the function of the completed assembly.” Many industrial products adhere to Class 2, where “continued performance and extended life is required, and for which uninterrupted service is desired but not critical.”

Class 3 is reserved for cable assemblies used in high-risk medical applications or in military technology, where “continued performance or performance on-demand is critical, equipment downtime cannot be tolerated, end-use environment may be uncommonly harsh, and the equipment must function when required.”

What is UL certification?

UL certifies parts to denote the amount of safety testing they’ve undergone prior to sale. This proves relevant when choosing components for a cable design or when trying to certify your own product.

UL certification comes in two forms: “UL listed” and “UL recognized.” UL recognized parts have passed through general safety testing, and UL listed parts have passed through safety testing particular to a certain use case. If you’re looking for a UL listed part, make sure the part is listed for your specific use case.

Your cable supplier may obtain a UL recognition for your custom cable assembly. This can make obtaining a UL listing for your product easier and provide more supply chain transparency to your customers.

Click through for a guide to UL listed and recognized cables.

The custom cable marketplace

If you’ve decided to outsource production of your custom cable assemblies, one of your most important decisions comes when choosing your cable assembly manufacturer. And different members of your team will prioritize different supplier traits, like lead times, quality control practices and contract terms.

But vastly different suppliers crowd the market, and it can be tough to choose the right partner. Some custom cable manufacturers prioritize driving down their own costs and passing those savings on to you. Some suppliers merely send your design to an offsite contract manufacturer and act as a sort of middleman.

Some custom cable suppliers, like Carlisle, are vertically integrated and can build custom components for your cable — but their minimum order requirements are extreme. Other more boutique suppliers can provide help with prototyping but lack the tools to scale production.

A few thoughtful questions about a supplier’s business model and capabilities should lead you to an understanding of whether they’re a right fit from a service, quality and price perspective.

Ask if they’re familiar with your application. Ask if they already have the necessary tooling or would need to acquire it. Ask if they offer any cable functionality guarantees and what quality control processes they use to ensure functionality.

Where Multi-Tek fits in

Multi-Tek is a mid-sized custom cable assembly manufacturer with our own manufacturing facility. We source components from the marketplace and assemble cables to meet design needs to a T. Our engineers can help customers finalize designs and improve manufacturability and cost when appropriate.

Because of our ability to perform robust quality control processes at a range of volumes, we excel when working with industrial companies who would pay dearly in the event of product failure. But our responsive communication and service flexibility helps us win for specialized consumer electronics companies as well.

Is Multi-Tek the right partner for you?

The simplest way to find out is to ask us. Let us know what you’re looking for, and we’ll tell you whether or not we’re a good fit. Request a quote, and you’ll receive a detailed response in less than three days.

Or you could read more about who we help and how.

If you have a cable engineering question or just want to talk to an expert, reach out. We love talking shop and specs.