Determining the right connector for your cable assembly


When designing cable and wire assemblies, correct connector selection is essential for overall performance. Connectors must reliably carry signal and power, all while working within your application’s space and environmental limitations.

And if an inappropriate connector is selected, there can be a number of adverse outcomes — intermittent connections, signal integrity issues, contamination, fire hazards — putting your entire system at risk.

Rather than enumerating every connector option on the market, we’ll use this article to guide you through the connector selection process. We’ll walk through the questions a cable assembly manufacturer will ask to make a best-fit recommendation, then discuss helpful guidelines to keep in mind as you consider your connector options.

When selecting a connector, be prepared to answer…

  • Will the cable be used to carry power or signal?
    • If power, how many amps will it need to carry?
    • If signal, what type of signal will it carry? Are extreme data transfer speeds required?
  • How many circuits will be required?
  • What are the space limitations of your device?
  • What sort of environment will the assembly be installed in?
    • Will there be chemical exposure?
    • What is the maximum and minimum temperature it will experience?
    • Will it be subjected to vibration, liquid exposure, direct sunlight or contaminants?
    • Will the connector be inside an enclosure, such as a panel mounted receptacle or plugged into a board, or will it be attached to a cable?

Once your cable assembly manufacturer has the answers to these questions, they’ll zero in on the connector series that makes the most sense for your application. They’ll balance economic and manufacturability concerns while factoring in bill of materials (BOM) and assembly costs as well.

Considerations for connector selection

These aren’t hard-and-fast rules for making a decision on a connector series. But these considerations — pulled from experience manufacturing thousands of cable assemblies — can save money and improve manufacturability in your design.

Work within your manufacturer’s existing equipment capabilities

Determine with your cable assembly partner if your connector series is compatible with their current tooling capabilities. If you can avoid tooling charges, it will make for a much more economical assembly — saving $4,000 to $8,000 in tooling costs.

Avoid unnecessarily small connectors when possible

Early in the design process (i.e. before circuit boards are laid out), it’s helpful to work in tandem with your in-house electrical engineer to choose the widest pitch connector possible for your application.

Unnecessarily small connectors are one of the largest contributors to increased cable assembly costs. As a rule of thumb, we recommend 2.54 mm pitch connectors whenever possible, as they are easier and more economical to assemble.

Understand the value of name brand

While some connectors are advertised as “form-fit-function” alternatives to their name brand counterparts, we recommend exercising caution when substituting with a generic connector.

Our assemblers often recognize the drop in quality right away: The terminals don’t seat properly in the housings and the connectors themselves don’t mate properly to the board. Additionally, these generic connectors will also make UL certification difficult or even unachievable.

Look first at Molex when choosing a connector. In our experience, these name brand options are well designed with connector families suitable for almost any application. They are also economical from a BOM cost standpoint and ease of assembly.

Commercial off-the-shelf cordsets provide an economical option

Commercial, molded off-the-shelf cordsets, such as M12, M8, RJ-45, C14 and USB cables, work great when connecting devices together: For example, M12 connectors are often used in factory automation settings to connect sensors and robotics equipment. And because these cordsets are produced in high volumes and are a standardized design, they provide an economical starting place when you need a different connector on one end, which may not be available for purchase off-the-shelf.

Consider alternatives for custom connectors

Designing a custom connector when there truly is no off-the-shelf option is a costly affair. It requires 16 to 24 weeks of lead time, high tooling costs and a partner with extensive CAD and engineering capabilities (something most cable assembly manufacturers don’t offer).

A great alternative to a completely custom connector is the HARTING Han-Modular® line. There are dozens of different connector inserts for almost any application — including fiber, data, coaxial and fiber optic — installed in a modular connector system configured to your exact needs.

Choosing this option instead of a completely custom connector can save thousands in tooling and development costs and help you avoid high minimum order quantities. Additionally, you’ll avoid dealing with a connector that no one has seen before, which can put a wrench in standardized installation and termination processes.

When in doubt, consult with your cable assembly manufacturer

We’ve seen it happen many times over — a connector checks all the boxes on paper, but when it comes time to manufacture, it proves slow or difficult to assemble, putting your deadlines and bottom lines at risk.
That’s where we come in.

At Multi-Tek, we’re the cable assembly experts so you don’t have to be. We’ll take a look at your design, make recommendations based on your application, budget and timeline parameters and help you achieve a design that performs without failure. Get a custom cable assembly quote.