Quick Answer
TPU coiled cable failures often begin where the moving cable meets a connector, overmold or straight tail. Buyers should specify connector part numbers, cable exit direction, straight-tail length, overmold envelope, bend transition, pinout, expected pull direction and how the assembly is mounted. The sample should be checked in the real device or a representative fixture for connector fit, cable routing, normal working extension, return behavior, continuity and movement near the termination. A visually clean overmold is not enough if its geometry transfers coil force into the contacts or blocks installation.
Why the Termination Is a High-Risk Area
A coiled cable stores and releases force as it extends and returns. That force can concentrate near the end of the coil, the straight tail, a crimp, solder joint, connector entry or molded transition. The actual risk depends on the installation, conductor bundle, cable diameter, connector design and operator movement.
There is no universal strain-relief shape that suits every application. A handheld microphone, test instrument, emergency-stop pendant and charging signal lead can require different exit directions, bend transitions and mounting clearances.
Seven Termination Details to Confirm
| Design detail | Buyer question | Sample evidence |
|---|---|---|
| Connector identity | What exact connector and mating part are used? | Part number, drawing and fit check. |
| Pinout | How are every conductor, shield and drain wire terminated? | Wiring diagram and continuity record. |
| Exit direction | Does the cable leave straight, angled or in a defined orientation? | Installed sample photo or fixture review. |
| Straight-tail length | Is there enough free length between the coil and termination? | Dimension check on both ends. |
| Overmold envelope | Will the molded body fit the device and nearby components? | Envelope drawing and mating test. |
| Bend transition | Does the transition avoid an abrupt stiffness change? | Movement observation under normal reach. |
| Pull direction | Which end moves, and how is the fixed end retained? | Representative extension and routing check. |
Start With the Installed Geometry
Provide the installation space before approving an overmold. A connector may fit by itself but fail once the cable is bent, the device cover is installed or the user pulls from an angle. Equipment photos, a 3D envelope, panel thickness, mating depth and nearby obstructions can prevent repeated sample revisions.
When a customer sample already exists, identify which dimensions and handling characteristics must be copied and which can change. Do not rely on a photo to reproduce hidden pinout, materials or internal retention.
Straight Tails Are Part of the Coil Specification
The straight sections between the coil and connector influence routing and force transfer. A tail that is too short can make the first coil turn carry connector movement. A tail that is too long may interfere with storage, appearance or equipment movement.
Specify the left and right tails separately, including where measurement begins and ends. Also identify whether the cable exits tangentially or axially from the coil and whether one end is fixed.
Overmolding Options Need Real Material Review
An overmold can provide shape, handling, insulation and a controlled transition, but performance depends on the connector, cable jacket, mold design, selected materials and process. Do not assume that an overmold automatically creates a waterproof rating or a defined pull-force value.
If sealing is required, define the complete interface and test method, including the mating connector, panel interface and unmated condition. For exposed equipment, review the marine waterproof TPU coiled cable page without treating the product name as proof of an ingress rating.
How Coil Force Affects the Connector
Normal working extension should not place unnecessary load on solder joints, terminals or the device receptacle. The finished cable’s force depends on conductor structure, cable diameter, jacket, coil dimensions and processing. Buyers should provide the normal reach and device mounting arrangement, then assess the sample in the intended direction of movement.
A temporary maximum extension can be recorded separately, but it should not replace the normal operating distance in the RFQ.
Sample Approval Checklist
- Connector identity, mating fit, locking action and orientation.
- Pinout and continuity for every circuit.
- Shield or drain-wire termination where applicable.
- Overmold dimensions and clearance in the installed equipment.
- Relaxed length, working extension, coil OD and both straight tails.
- Cable exit direction and movement at the fixed and moving ends.
- Return behavior after an agreed extension sequence.
- Appearance around the mold interface and cable surface.
- Packaging restraint and coil condition after unpacking.
Testing Should Match the Drawing and Use Case
Available checks can include dimensions, conductor continuity, pinout, connector fit, movement, extension, return behavior and project-specific pull or bend checks. The buyer and supplier should agree on the fixture, cable state, direction, cycle or dwell condition and acceptance limit before treating a test result as meaningful.
Refer to the testing and quality equipment page and the TPU RFQ worksheets when preparing the sample-approval record.
Common Purchasing Mistakes
- Approving an overmold from appearance without checking installed clearance.
- Omitting the mating connector or panel interface.
- Providing one straight-tail dimension when the two ends are different.
- Ignoring which end is fixed and which end moves.
- Requesting a pull test without defining direction, fixture and pass/fail limit.
- Assuming molded construction automatically provides a waterproof rating.
- Testing maximum extension but not normal working reach and return.
Buyer Checklist
- Application, device photos and installation envelope.
- Connector and mating-part drawings.
- Pinout, conductor count, gauge and shielding.
- Relaxed length, working extension, coil diameter and straight tails.
- Exit direction, fixed end, moving end and typical pull direction.
- Overmold shape, color, marking and material requirements.
- Sample test method and measurable acceptance criteria.
- Sample quantity, annual demand, labels and packaging.
What to Send in the RFQ
Send the connector and mating-part information, wiring diagram, equipment photos, installation dimensions, desired coil geometry, normal reach, movement direction, expected quantity and required inspection method. If the overmold shape is not final, identify the available space and handling problem before requesting tooling.
Related Products and Case Evidence
Explore the custom TPU coiled cable product range, review the emergency-stop safety coiled cable, and see the batch length inspection and packaging case for practical specification and receiving considerations.
Upload RFQ
Drawings do not need to be complete before the first review. Upload connector details, equipment photos and your TPU coiled cable requirements to begin specification review.
FAQ
Does a longer strain relief always improve cable life?
No. Geometry must suit the connector, cable, available space and movement. A longer or stiffer transition can create a different stress point.
Can an existing sample be copied without a drawing?
A sample helps define dimensions and handling, but hidden wiring, materials and acceptance criteria still need confirmation.
Should pull testing be included in every project?
Use project-relevant checks. When pull testing is required, define the fixture, direction, load, duration and acceptance result.