A photo used as the only drawing
Hidden connections and dimensional datums remain ambiguous. Use a controlled connection table and harness drawing.
Services / PROJECT FIELD GUIDE
Cable & Wire Harness Assembly
Specify the connections between boards, power supplies and the finished product.
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Less guesswork. A clearer release.
- Understand the relevant choices
- Compare requirements and next steps
- Download useful notes for your review
What to know before you decide
A custom cable assembly needs a controlled connection map and a mechanical definition, not simply a photograph of a sample. Specify connectors and contacts, wire type and size, circuit destinations, length datums, shielding and environmental requirements. Then choose inspection and electrical tests that detect the faults relevant to the application. The mating interface and terminal application specification should guide the design; connector families can use different contacts, seals and tooling.
01 / DECISION GUIDE
Make the trade-offs explicit
01
Draw both electrical and physical identity
Use pin numbers tied to an explicit viewing direction at each connector. A mating-face drawing and a wire-entry drawing can look reversed. Label branches and distinguish wire color from circuit identity. Include connector housings, contacts, seals and accessories as separate controlled items so that purchasing does not select an incomplete combination.
02
Define length with reproducible datums
State where each dimension begins and ends, and whether it applies before or after dressing the harness. Specify branch locations, breakout orientation and any installation bend constraints. A nominal overall length measured differently by two people can create an unusable harness. Review the assembly in its intended enclosure or routing path before freezing tolerances.
03
Match the crimp system to the wire
Use the terminal maker's applicable wire range, insulation requirements and tooling guidance. Define the required evidence for the product, such as process setup verification or pull testing where appropriate. Avoid selecting a terminal only by conductor size: insulation diameter and seal compatibility can matter too. Record the approved terminal and wire combination as a system.
04
Choose tests for the actual circuits
A continuity check can find an open wire but may not establish correct pin mapping or acceptable insulation. Define the netlist and any resistance, insulation or dielectric test requirements from the product needs. Protect sensitive components inside the harness from incompatible tests. Keep serial or batch identification linked to results when traceability is required.
Compare the choices
| Requirement | What to document | Error it helps prevent |
|---|---|---|
| Pinout | Connector view and cavity numbers | Mirrored or crossed circuits |
| Mechanical route | Length datums and branch positions | Poor installation fit |
| Termination | Wire, contact, seal and tooling system | Incompatible crimp combination |
| Shielding | Connection points and termination method | Unintended shield discontinuity |
| Electrical test | Netlist and appropriate pass limits | Undetected wiring or insulation faults |
Questions that prevent rework
Wire color mistaken for circuit identity
Repeated colors and supplier changes can create confusion. Tie every circuit to connector cavity numbers.
Unspecified shield treatment
State where shields and drains terminate and where they remain isolated. Do not leave this to assembly interpretation.
Get a clear answer
What is needed to quote a cable assembly?
Provide a pin-to-pin table, connector and contact part numbers, wire specification, dimensions with datums, quantity and test requirements. Include routing or environmental constraints that affect construction.
Does continuity testing prove the harness is correct?
Only if the test includes the correct connection map, and even then it does not prove all mechanical or insulation requirements. Select additional checks based on the product's failure risks.
Can an equivalent connector be substituted?
Review the complete mating and termination system first. Housing appearance does not prove contact, seal, latch or electrical compatibility.
Technical references
Check each source’s scope and revision against your project requirements. Confirm the proposed construction with your manufacturing partner.
YOUR PROJECT / YOUR NEXT STEP
Build a useful project brief
Prepare a harness review brief without assuming a universal crimp or electrical-test limit.
Use this planning aid to prepare a review. It does not approve a design or estimate a price. Selections are processed locally and are not submitted by this tool.