Design & Materials
Strain Relief, Bend Radius, and Routing Inputs
Strain relief works as part of an installed route, not as an isolated shape. Show the connector or termination, cable construction, exit direction, first bend, support points, movement, keep-out space, molded or mechanical relief, and the method used to judge the assembly.
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Decision summary
What to carry into the decision
- Draw the cable path from the termination through the first bend and nearest support.
- Use cable and component data plus the equipment design criteria to set bend and routing limits.
- Separate static routing, installation movement, service movement, and repeated operating motion.
- Define pull, flex, sealing, fit, or other checks with a method and acceptance limit.
In this guide
- 1Draw the installed route
- 2Routing input table
- 3Choose the strain‑relief function
- 4Separate movement conditions
- 5Define useful validation
- 6Common routing mistakes
Use the sections in sequence, then turn the open items into one controlled build or sourcing package.
Draw the installed route
Show the connector or termination datum, cable exit direction, first bend, minimum available space, clips or ties, pass-throughs, contact surfaces, branch points, and the equipment position during installation, use, and service.
Mark where the cable must remain flexible and where it should be supported. A close connector drawing without the surrounding route cannot answer that question.
Routing input table
Describe the condition that each dimension represents.
| Interface | Connector, terminal or splice; mating direction; cable exit; overmold, boot, grommet or clamp; and keep-out space. |
|---|---|
| Cable | Construction, outside diameter and tolerance, flexibility, shield, jacket, temperature and exposure inputs, and supplier data. |
| Route and movement | Bend location and radius, supports, rubbing or heat zones, installation movement, service movement, repeated motion, and torsion. |
| Validation | Fit, pull, flex, retention, sealing, electrical or functional method, fixture, sequence, limits, and post-check. |
Choose the strain-relief function
State what the relief must do: distribute bending, reduce load at a termination, hold a cable position, seal an opening, protect an edge, or provide a mounting feature. Different functions can require different geometry and materials.
Identify whether the relief is molded, assembled as a separate part, integrated into the connector, or created by equipment-side support.
Separate movement conditions
Use distinct rows so a one-time installation bend is not mistaken for continuous flex.
- Static installed route after assembly.
- Installation motion needed to connect or route the cable.
- Service access used during maintenance or replacement.
- Repeated operating movement, coil extension, drag, vibration, or torsion.
Define useful validation
Choose a test that reproduces the important load or motion with clear setup, cycles or duration, limits, sample condition, and post-test inspection. A pull check at the connector does not automatically cover repeated flex along a route, and a flex test does not prove a sealing target.
Record electrical continuity or other post-checks when the equipment program uses them to detect hidden damage.
Common routing mistakes
Avoid setting a bend radius without identifying the cable construction and measurement condition, placing the first bend inside the connector keep-out, or adding a relief shape that cannot fit the equipment. Do not let packing create a tighter bend than the installed design allows.