Overmolded vs Potted Cable Assembly: Which Encapsulation Method?
The definitive 2026 guide to choosing between overmolding and potting for your cable assemblies. Learn material options, cost breakpoints, and why the right choice depends on your production volume.
When designing cable assemblies for harsh environments, the junction between connector and cable is the most vulnerable point. Environmental sealing, strain relief, and mechanical protection all converge at this critical interface. The two primary methods for encapsulating this junction—overmolding and potting—each have distinct advantages depending on your volume, budget, and performance requirements.
With 18+ years manufacturing sealed cable assemblies for automotive, medical, and mining applications, we've produced millions of both overmolded and potted assemblies. Here's what we've learned about when each method excels.
Quick Verdict: Volume Is the Deciding Factor
The breakeven point is typically 500-2,000 units. Below this volume, potting is more economical due to minimal tooling. Above this volume, overmolding's faster cycle times and consistency make it the better choice. For safety-critical or high-reliability applications, overmolding is preferred regardless of volume.
Choose Overmolding When:
- • Production volume >1,000 units
- • Consistent IP67/IP68 sealing required
- • Fast production cycle needed
- • Aesthetic appearance matters
- • Medical/automotive standards apply
- • Long-term cost optimization
Choose Potting When:
- • Production volume <500 units
- • Prototyping or design iteration
- • Cannot justify tooling investment
- • Irregular connector geometries
- • One-off or custom designs
- • Budget constraints on upfront costs
How Overmolding Works
Overmolding is an injection molding process where a pre-assembled cable and connector are placed into a mold cavity. Molten thermoplastic material is then injected under high pressure, encapsulating the junction and forming a seamless, integrated unit. Once the plastic cools (typically in seconds), the assembly is ejected as a complete, sealed product.
The Overmolding Process
- 1Assembly: Cable is terminated to connector using standard crimping or soldering
- 2Placement: Assembly is positioned in precision-machined mold tool
- 3Injection: Molten thermoplastic (150-250°C) injected at high pressure
- 4Cooling: Material solidifies in 15-60 seconds depending on mass
- 5Ejection: Finished assembly removed, ready for testing
Overmolding Advantages
Superior Environmental Sealing
Injection pressure ensures complete encapsulation with no voids. Achieves consistent IP67/IP68/IP69K ratings with proper mold design.
Excellent Strain Relief
The molded boot transitions gradually from rigid connector to flexible cable, distributing mechanical stress and preventing flex fatigue at the termination point.
Fast Production Cycle
Cycle times of 30-90 seconds enable high-volume production. No curing time required—assemblies are ready for testing immediately.
Repeatable Quality
Process parameters (temperature, pressure, time) are precisely controlled. Every unit is identical, reducing quality variation and inspection requirements.
Overmolding Disadvantages
- High Tooling Cost: Custom molds cost $5,000-50,000+ depending on complexity. Multi-cavity molds for higher volume cost more but reduce per-unit cost.
- Design Inflexibility: Once tooled, design changes require new molds or expensive modifications. Not suitable for iterative development.
- Material Compatibility: Not all cable jacket and overmold materials bond well. TPU cable with TPE overmold, for example, may have adhesion issues.
- No Repair Possible: Failed assemblies cannot be repaired—the overmold must be destroyed to access the termination. Entire assembly must be replaced.
How Potting Works
Potting involves filling a connector backshell or housing with a liquid compound that cures to a solid over time. The compound—typically epoxy, polyurethane, or silicone—flows around the terminations and cable entry, then hardens to create an environmental seal and provide strain relief.
The Potting Process
- 1Assembly: Cable terminated and inserted into backshell or potting cup
- 2Mixing: Two-part compound mixed immediately before application
- 3Dispensing: Compound poured or injected into backshell cavity
- 4Degassing: Vacuum applied to remove air bubbles (optional but recommended)
- 5Curing: Compound solidifies over 30 minutes to 24+ hours depending on type
Potting Advantages
Minimal Tooling Investment
No expensive injection molds required. Potting cups, backshells, and dispensing equipment cost a fraction of molding tooling.
Design Flexibility
Can accommodate irregular geometries, varying cable diameters, and non-standard connectors without custom tooling.
Material Options
Wide range of compounds from rigid epoxy to flexible silicone. Can optimize for thermal conductivity, chemical resistance, or flexibility.
Low Process Temperature
Cures at room temperature or with gentle heat. No risk of thermal damage to sensitive components or low-temperature cable materials.
Potting Disadvantages
- Slow Cycle Time: Curing takes 30 minutes to 24+ hours. This bottleneck limits daily production capacity and increases work-in-progress inventory.
- Process Variability: Mix ratios, dispensing technique, and curing conditions all affect quality. More skill-dependent than automated overmolding.
- Void/Bubble Risk: Air trapped during dispensing creates voids that compromise sealing. Requires vacuum degassing for critical applications.
- Messy Process: Liquid compounds can overflow, drip, or migrate. Requires careful containment and cleanup, adding labor cost.
- Higher Per-Unit Cost at Volume: Labor-intensive process doesn't scale efficiently. Per-unit cost stays relatively flat as volume increases.
Encapsulation Materials Compared
Overmolding Materials
| Material | Characteristics | Best Applications | Cost |
|---|---|---|---|
| PVC | Rigid, good electrical insulation, easy to process | Consumer electronics, low-cost applications | $ |
| TPE | Flexible, UV/ozone resistant, chemical resistant | Outdoor equipment, industrial, medical | $$ |
| TPU | High abrasion resistance, elastic, excellent durability | Medical, automotive, harsh environments | $$ |
| Silicone | Wide temp range (-60 to +200°C), biocompatible | Medical implants, aerospace, high-temp | $$$ |
Potting Compounds
| Compound | Characteristics | Cure Time | Best Applications |
|---|---|---|---|
| Epoxy | Rigid, excellent adhesion, high chemical resistance | 4-24 hours | Electronics, high-temp, structural |
| Polyurethane | Semi-flexible, good impact resistance, lower exotherm | 2-12 hours | Automotive, industrial, outdoor |
| Silicone | Very flexible, wide temp range, easy rework | 30 min - 4 hours | Medical, aerospace, thermal cycling |
Material Compatibility Warning
Not all material combinations bond well. If the overmold material doesn't chemically bond with the cable jacket, water can penetrate the interface. Always verify compatibility—for example, TPE overmold on TPU cable jacket may have adhesion problems. Request material compatibility testing from your manufacturer before committing to tooling.
Head-to-Head Comparison
| Factor | Overmolding | Potting |
|---|---|---|
| Tooling Cost | $5,000-50,000+ | $100-500 ✓ |
| Per-Unit Cost (High Vol.) | Lower ✓ | Higher (labor-intensive) |
| Cycle Time | 30-90 seconds ✓ | 30 min - 24 hours |
| Process Consistency | Excellent ✓ | Operator-dependent |
| IP Rating Consistency | Very consistent ✓ | Variable (void risk) |
| Design Flexibility | Fixed by mold | Highly flexible ✓ |
| Prototype Friendly | No (tooling required) | Yes ✓ |
| Aesthetic Finish | Professional, uniform ✓ | Variable, less refined |
| Strain Relief Quality | Integrated, graduated ✓ | Abrupt transition |
| Repairability | None | None |
Table: Direct comparison of overmolding vs potting for cable assembly encapsulation. Green checkmarks indicate the better option for each factor.
Cost Analysis: Finding Your Breakeven Point
The total cost of ownership depends heavily on production volume. Overmolding has high upfront costs but low marginal costs; potting has the opposite profile. Understanding where these curves cross is essential for making the right decision.
Cost Structure Comparison
Overmolding Costs
- Mold tooling (simple)$5,000-15,000
- Mold tooling (complex)$15,000-50,000
- Multi-cavity molds$30,000-100,000+
- Per-unit cost (at volume)$0.50-3.00
Potting Costs
- Potting cups/backshells$2-20 each
- Dispensing equipment$500-5,000
- Compound (per unit)$1-10
- Labor (per unit)$5-20
Typical Breakeven Analysis
For a standard connector overmold with $10,000 tooling cost and $1.50 per-unit molding cost versus $8 per-unit potting cost:
Breakeven Point: ~1,540 units
- • At 500 units: Potting saves ~$3,250
- • At 1,000 units: Potting saves ~$500
- • At 2,000 units: Overmolding saves ~$3,000
- • At 10,000 units: Overmolding saves ~$55,000
"The tooling investment is always the sticking point for first-time customers. But I show them the math: a $15,000 mold amortized over 50,000 units is $0.30 each. The same assembly potted costs $8-12 each. Over the product lifetime, overmolding pays for itself ten times over—and the quality consistency is incomparable."
— Manufacturing cost perspective
Application-Specific Recommendations
Medical Devices
Recommended: Overmolding (TPE or TPU)
Medical cables require consistent sealing for sterilization compatibility, smooth surfaces for cleaning, and documented process control. Overmolding provides the repeatable quality required for FDA/TGA compliance. TPE and TPU materials can withstand autoclave cycles when properly specified. Learn more in our medical cable compliance guide.
Mining & Heavy Industry
Recommended: Overmolding (TPU) for production; Potting for field repairs
Mining equipment demands IP69K sealing, extreme abrasion resistance, and resistance to hydraulic fluids and diesel. TPU overmolding excels in these conditions for production volumes. However, potting remains valuable for field repairs where damaged cables must be sealed on-site without replacement. See our mining IP69K guide.
Industrial Automation
Recommended: Overmolding for standard sensors/actuators; Potting for custom one-offs
Industrial sensor cables are produced in high volumes where overmolding cost advantage is clear. The consistent M12/M8 connector formats make tooling reusable across product lines. For custom machine builds or prototype systems, potted assemblies avoid tooling delays during commissioning.
Robotics
Recommended: Overmolding with graduated strain relief
Robot cables experience millions of flex cycles. The graduated strain relief possible with overmolding distributes stress over a longer length, dramatically improving flex life. Potted cables with abrupt transitions fatigue faster at the boundary. Our robotics cable guide covers flex life specifications.
Prototyping & Low-Volume
Recommended: Potting (polyurethane or silicone)
During product development, designs change frequently. Committing to overmolding tooling before design freeze is risky. Potting allows quick iteration—if the connector or cable changes, only the backshell needs adjustment. Transition to overmolding when design is stable and production volume justifies tooling.
"I've seen companies spend $20,000 on overmold tooling for a 200-unit prototype run, then change the design twice. And I've seen companies pot 50,000 assemblies by hand because they 'couldn't justify' tooling costs. Both are expensive mistakes. The question isn't which method is better—it's which method is right for your volume, your timeline, and your quality requirements. Get that assessment right, and the rest follows."
Hommer Zhao
Technical Director, OurPCB Australia
18+ Years Cable Assembly Manufacturing Experience
Frequently Asked Questions
What is the difference between overmolded and potted cable assemblies?
Overmolding uses injection molding to encapsulate cable junctions with thermoplastic (TPE, TPU, PVC) in seconds. Potting fills backshells with liquid compound (epoxy, polyurethane, silicone) that cures over hours. Overmolding is faster and more consistent for high volumes; potting is more economical for low volumes and prototypes.
Which encapsulation method is better for IP67/IP68 sealing?
Both methods can achieve IP67 and IP68 ratings when properly executed. Overmolding provides more consistent sealing due to controlled process parameters. Potting can achieve excellent sealing but is more dependent on operator skill and void-free application. For critical waterproofing, overmolding is generally preferred.
What are the cost differences between overmolding and potting?
Overmolding has higher tooling costs ($5,000-50,000+ for molds) but lower per-unit costs. Potting has minimal tooling costs but higher labor and material costs per unit. The breakeven point is typically 500-2,000 units—below this, potting is cheaper; above this, overmolding becomes more economical.
Can overmolded or potted cables be repaired?
Neither overmolded nor potted cable assemblies can be repaired without destroying the encapsulation. Both are designed as permanent, sealed units. If the cable or connection fails, the entire assembly must be replaced. This is why quality control during manufacturing is critical for both methods.
What materials are used for overmolding?
Common overmolding materials include PVC (lowest cost, good for indoor use), TPE (flexible, UV-resistant, suitable for outdoor), TPU (high abrasion resistance, medical/automotive), and silicone (widest temperature range, biocompatible). Material choice depends on environmental requirements and cable jacket compatibility.
How long does potting compound take to cure?
Cure time varies by compound type: silicone typically cures in 30 minutes to 4 hours, polyurethane in 2-12 hours, and epoxy in 4-24 hours. Elevated temperature can accelerate curing. This slow cycle time is a key disadvantage of potting for high-volume production.
Sources & References
Need Custom Overmolded or Potted Cable Assemblies?
With 18+ years of experience and in-house injection molding capability, we deliver both overmolded and potted cable assemblies. From prototype quantities to million-unit production, our team helps you choose the right encapsulation method for your application and budget.
In-House Molding
Custom mold design and production under one roof
IP67/IP68/IP69K
Certified sealing for harsh environments
Volume Flexibility
From 10-piece prototypes to 100K+ production