OVERMOLDED VS. NON-OVERMOLDED CABLE ASSEMBLIES: WHAT’S RIGHT FOR YOUR APPLICATION?

Introduction: Not All Cable Assemblies Are Created Equal

When developing rugged electronic systems, selecting the right cable assembly can make or break long-term performance. Designers often face a key decision: whether to specify an overmolded or non-overmolded cable assembly.

Both approaches have value, but they address different engineering goals whether you're building for extreme durability, tight space constraints, EMI shielding, or ease of service. The wrong choice can lead to premature wear, increased signal noise, or unexpected failure in harsh environments.

At Meritec, we work with OEMs and system engineers across aerospace, defense, industrial automation, and medical markets. In this post, we’ll clarify the differences between overmolded and non-overmolded designs and help you determine which approach best matches your application.

What Is an Overmolded Cable Assembly?

An overmolded cable assembly is built by injecting a polymer material typically a thermoplastic or elastomer around the junction where the connector meets the cable. This process creates a seamless, encapsulated transition between cable and connector.

The resulting assembly offers several benefits:

• Enhanced strain relief that prevents mechanical stress at the connector interface.
• Environmental sealing for resistance to moisture, dust, chemicals, and temperature extremes.
• Vibration damping to protect internal terminations and reduce fatigue under dynamic motion.
• Improved aesthetics and ergonomics important for handheld devices or visible installations.

At Meritec, overmolded assemblies are often used in field-deployable military systems, avionics, medical devices, and industrial robots platforms where ruggedization and ingress protection are key.

What Is a Non-Overmolded Cable Assembly?

In a non-overmolded cable assembly, the connector is typically crimped, soldered, or otherwise mechanically terminated to the cable, and then protected with shrink tubing, backshells, or mechanical strain relief.

Non-overmolded designs provide:

• Greater flexibility in connector selection, particularly for specialized MIL-DTL or circular connector styles.
• Serviceability, as connectors can often be disassembled or replaced in the field.
• Adaptability for low-volume or prototype systems where tooling costs for overmolding are not justified.

Meritec frequently supplies non-overmolded assemblies for aerospace harnesses, ground vehicles, and development test equipment where modularity and field-serviceability matter more than environmental sealing.

Comparing Overmolded and Non-Overmolded Assemblies

How Environmental Demands Drive the Right Choice

One of the primary factors in choosing between overmolded and non-overmolded assemblies is the operating environment.

In harsh outdoor environments such as oil rigs, military vehicles, aircraft exteriors, and shipboard systems exposure to water, dust, chemicals, or salt spray makes overmolded designs a smart choice. The polymer encapsulation prevents ingress and locks the mechanical interface in place.

For lab, aerospace interior, or modular development platforms, non-overmolded solutions often provide more flexibility. In these cases, engineers may prioritize access to connectors for maintenance or modular upgrades, and environmental protection is achieved through controlled enclosures rather than sealed connectors.

Vibration and Mechanical Stress: Which Holds Up Better?

In environments subject to constant vibration aircraft, combat vehicles, rail systems strain relief is critical. Overmolded assemblies offer superior performance here because the molded polymer distributes stress across a wide area and prevents micro-movements at the connector transition.

Without proper strain relief, non-overmolded assemblies may experience long-term fatigue at the cable-to-connector interface. However, when combined with high-quality backshells and correct cable management, non-overmolded designs can still perform well in demanding applications.

Volume and Cost Considerations

For large production runs, the initial tooling investment in overmolding is amortized quickly, and the long-term benefits in ruggedness justify the upfront cost.

In low-volume programs or prototyping stages, non-overmolded designs may be more practical because they avoid tooling expense and allow rapid iteration. Meritec works with many aerospace and defense customers during development to prototype non-overmolded assemblies then transition to overmolding for production.

A Real-World Example: Military Field Electronics

One Meritec customer developing a tactical field computer originally used non-overmolded assemblies in early prototypes. As the product approached deployment, field testing revealed issues with moisture ingress and vibration fatigue in exposed cable terminations.



Meritec’s engineering team recommended transitioning to an overmolded assembly using a specialized low-durometer polymer that maintained flexibility while providing sealing and shock protection. The new assembly passed MIL-STD environmental tests, and production units have since seen successful field use across multiple global deployments.

Why Engineers Rely on Meritec

At Meritec, we don’t take a one-size-fits-all approach. Our engineers consult closely with customers to determine the right construction method for each application.

We bring:

• Deep knowledge of overmolding materials, processes, and environmental standards.
• Expertise in traditional non-overmolded designs, including MIL-DTL circular and rectangular interfaces.
• In-house design and manufacturing for both overmolded and non-overmolded assemblies.
• Rapid prototyping capabilities to support development cycles.
• Testing and qualification to military and aerospace standards.



Whether your program demands sealed overmolded designs for IP-rated ruggedness, or flexible non-overmolded harnesses for aerospace integration, Meritec delivers assemblies that perform in the real world.

Build the Right Cable Assembly with Meritec 

Choosing between overmolded and non-overmolded cable assemblies requires careful consideration of environmental demands, mechanical stress, connector options, and project scale. No matter which path is right for your system, Meritec provides the expertise and manufacturing capability to deliver.

Let’s engineer the right solution for your next project whether it flies, rolls, sails, or computes in the toughest environments.

Explore Meritec’s custom cable assemblies: https://www.meritec.com

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