Cable & wire harness sourcing
Cable assembly and wire harness sourcing guide
The right cable manufacturer for your program is the one whose workmanship class, test capability and paperwork match what your drawing actually requires. This guide shows you how to tell, before the first article arrives.
How to choose a manufacturer
The qualification questions that separate a capable cable shop from a confident one, and how to verify each answer yourself.
Supplier checklist →IPC/WHMA-A-620 classes
Class 1, 2 and 3 in plain terms: what changes between them, and how to choose one for your part.
Workmanship classes →RFQ checklist
What to send so that five quotes come back for the same part, and not five different interpretations of it.
Build the package →Cable assembly vs wire harness
Two terms often used interchangeably, which are built, quoted and inspected differently.
Know the difference →All guides
Qualifying a supplier
- How to choose a cable assembly manufacturer — the qualification questions, and how to check each answer.
- How to verify AS9100, ISO 9001, ITAR and UL claims — where each credential's independent record lives, and what to read in it.
- Wire harness supplier audit checklist — a shop-floor checklist from receiving to shipping.
Specifying the part
- Cable assembly vs wire harness — the difference, and where box build fits.
- IPC/WHMA-A-620 classes 1, 2 and 3 — what changes between them, and how to choose.
- What to put on a wire harness drawing — layout, pinouts, BOM and the notes most often missed.
- Overmolded cable assemblies — when a molded end is worth it, and what to ask about tooling.
Quality, test and approval
- Cable assembly testing — continuity, insulation resistance and hipot, and how to write the test note.
- Crimp pull testing and crimp height — how a supplier proves every crimp is right.
- AS9102 first article inspection — the three forms, applied to a harness.
- PPAP for wire harnesses — submission levels and the 18 elements for automotive work.
Quoting, cost and schedule
- Cable assembly and wire harness RFQ checklist — what to send so quotes come back comparable.
- What drives the cost of a custom wire harness — and how to lower it without lowering the part.
- Custom cable assembly lead times — what sets them, and how to shorten them.
Why sourcing cable assemblies goes wrong
Cable assemblies and wire harnesses look simple on a drawing: wire, terminals, connectors, some sleeving. That simplicity is exactly why sourcing them goes wrong. Almost every shop can crimp a terminal. Far fewer can prove, part after part, that the crimp was made with the right tool, set up correctly, on wire from a traceable lot, and tested to the requirement on your drawing rather than to their own habit.
Most sourcing problems with cable and wire harness assemblies trace back to one of three gaps:
- An unstated workmanship class. If the drawing does not call out an IPC/WHMA-A-620 class, a supplier will build to whatever class they usually build to, and a quote that looks cheaper may simply be for a lower class.
- An unverified credential. Quality-system certificates and export registrations can be checked independently. Buyers who check them before issuing a purchase order avoid the most expensive kind of surprise.
- An incomplete RFQ package. Missing test requirements, labeling rules or approved alternates turn into assumptions, and assumptions turn into non-conformances at receiving inspection.
How to use this guide
If you are qualifying a new cable assembly supplier, start with how to choose a manufacturer, then check the credentials the supplier gives you. If you are writing or reviewing a drawing, read the IPC/WHMA-A-620 class guide first, because the class you choose drives inspection, cost and lead time. If you already have a supplier shortlist, the RFQ checklist will make their quotes comparable.
This guide does not rank manufacturers. A ranked list cannot know your part, your volumes or your compliance obligations, so any "top ten" is really just advertising. What we can give you instead is the method for judging any supplier, including the one that publishes this guide.
Markets this guide covers
The guidance applies across industries, with notes where requirements diverge: aerospace (AS9100 quality systems, first article inspection to AS9102), defense (ITAR, DFARS flowdowns and counterfeit-part controls), automotive (IATF 16949, PPAP, and USCAR connector and crimp specifications) and industrial equipment, where the requirements are usually set by your own drawing. Cables for trailers, containers and cargo equipment are covered on our sister guide, cargocables.com.
Sourcing terms used in this guide
| Term | Meaning |
|---|---|
| Build to print | The supplier builds to your drawing; you own the design |
| FAI | First article inspection, often to AS9102 in aerospace |
| PPAP | Production Part Approval Process, used in automotive |
| NRE | Non-recurring engineering: one-time set-up and tooling cost |
| Formboard | Full-size board used to lay out and build a harness |
| DWV / hipot | Dielectric withstanding voltage test of insulation |
| CoC | Certificate of conformance supplied with a shipment |
| Flowdown | A requirement passed from your customer's contract to your supplier |
Common questions
Is there a list of the best cable assembly manufacturers here?
No. A ranking cannot know your part, volumes or compliance obligations. This guide gives you the questions and checks to judge any supplier yourself.
Who publishes this guide?
Aerotier Manufacturing LLC, a cable assembly and wire harness manufacturer in start-up. The about page explains how the guide is written with that in mind.
Does this guide replace the published standards?
No. It summarizes standards such as IPC/WHMA-A-620, AS9102 and the AIAG PPAP manual for buyers. For anything contractual, read the current edition of the standard itself.