How to Prepare a Cable Assembly Drawing

A useful cable assembly drawing lets the buyer, assembler and reviewer identify the same build without guessing. It connects the component list, circuit map, physical dimensions and revision history. A neat outline alone cannot do that.

Start with the requirements you know and mark unresolved fields openly. A sketch can support an initial discussion, but a document containing unresolved connector references or circuit assignments should not be released as a manufacturing instruction. The cable assembly RFQ checklist covers the wider quotation package; this guide explains how the drawing itself fits together.

Start with one controlled example

FOR REVIEW ONLY. Lettered cavities are placeholders, not official pin numbers; the incomplete example cannot authorize manufacturing.

The example below is fictional and incomplete: EX-CA-014, Revision A, FOR REVIEW ONLY. It describes three wires between two four-position housings. It is not a Zeakka product, customer drawing, connector specification or approved electrical design.

Give the drawing an assembly number, revision, date, sheet count and status. Use J1 and J2 consistently for the two ends. If the BOM or connection list lives in a separate file, record its identifier and revision on the drawing. Export a readable review PDF and retain the editable source under the same document-control process.

A reviewer should be able to answer: which files belong together, which version supersedes the previous one, and who can authorize release?

Identify both connector ends in the BOM

“Four-pin connector” or a family name is insufficient. Identify the exact manufacturer and housing reference, terminal reference, quantity and any secondary lock, seal or accessory. Record the equipment-side mating references separately, even when those parts are not supplied with the cable.

Do not assume the same terminal suits both ends. Conductor size and insulation diameter must fit each selected termination. JST's handling precautions direct users to confirm wire applicability for the chosen terminal and consult the relevant handling instructions.

If an alternative is allowed, identify its supplier and exact reference in a separate proposed BOM. “Or equivalent” must not conceal an unresolved substitution.

Connect the circuit table to explicit views

A circuit table describes connectivity; a connector view locates those circuits physically. Use both. Label each view as mating face or wire-entry side and show a recognizable key or latch. Verify the actual cavity numbering from the selected component drawing rather than assigning pin 1 from a photograph.

For example, the official JST GH catalog identifies circuit 1 in its component drawings. That information belongs to the parts and views shown there; it is not a universal numbering convention for other housings.

Our fictional map uses lettered placeholders specifically to avoid claiming official pin numbers:

Before release, replace every placeholder with the verified cavity number and supply the corresponding views. Resolve wire specification and identification for each row. Color assists identification; it does not establish connectivity. Use the pinout and viewing-direction guide for a fuller orientation check.

Define what each length measures

State units and point to the exact reference surfaces. For this fictional review, choose the rear housing exit planes at J1 and J2 as length endpoints, then mark the target and tolerance TO BE CONFIRMED. State how the flexible assembly is positioned for measurement without stretching it. This is a document convention to review, not a recommended production dimension.

Keep cut-wire length separate from finished assembly length. If you add a branch, sleeve, label or heat-shrink section, give it its own location and extent. Show connector orientation and cable-exit direction where they affect installation. A tolerance should come from the fit requirement and agreed measurement method, not an arbitrary default.

Replace vague instructions with reviewable requirements

Use the following wording patterns to expose missing decisions. They are prompts for your own drawing, not completed production specifications. Replace every bracketed field before release.

Do not specify a heat-shrink sleeve as a mechanical anchor merely by adding it to the drawing. If cable retention matters, identify the support and how it carries the load. Similarly, an empty cavity needs an explicit population instruction; a blank table cell should not leave the assembler guessing whether information was omitted.

Add notes that can be checked

Reference the agreed acceptance document and revision. Identify appearance, labeling, packaging or special evidence requirements where they affect this build. Avoid vague notes such as “high quality” or “fully tested.” The instruction needs an observable requirement, an agreed check and an acceptance criterion.

Do not copy a connector's catalog rating into an assembly-level guarantee. The selected wire, installation and application conditions still need review. Leave unresolved requirements visible in the issue list rather than embedding assumptions in the released drawing.

Separate quotation questions from release decisions

An initial request can contain open questions. Put them in an issue list with a decision owner, affected document and status. For example: the customer confirms the equipment-side header; the supplier proposes a terminal compatible with the selected wire; the customer reviews that proposal before it becomes the released BOM. A request for clarification is not approval to substitute a component.

Keep commercial quantities beside the RFQ rather than using them to redefine the assembly. State sample, first-production and repeat quantities separately. If the quotation is based on assumptions, ask for those assumptions to be listed. The resulting price should be understood as applying to that scope, not to every future revision.

For an assembly made from an existing sample, photograph both connector faces and wire-entry sides, show a scale for dimensions, and provide the known equipment-side references. Physical similarity does not establish the internal circuit map. Agree how that map will be verified before copying it into the drawing.

Close the loop before sampling

Walk through the package once as an independent reviewer: trace every connection, count contacts against populated cavities, check each end's BOM, and locate every dimension endpoint. Confirm the same revisions appear in the quotation, drawing and sample request.

If Revision B changes a connection, record the exact change and withdraw Revision A from active use. Keep the original revision available as history. When samples arrive, use the sample approval checklist to relate the actual build to the released documents.

Before release, use this short review sequence:

1. Match the drawing, BOM and connection-list identifiers and revisions.
2. Count housing positions, contacts and wires, including deliberately empty cavities.
3. Trace each connection against the labeled component views.
4. Locate each dimension's endpoints and the applicable tolerance.
5. Resolve substitutions, inspection criteria and remaining open questions with the responsible approver.

Frequently asked questions

Can I request a quotation without a CAD drawing?

Yes. Start with a marked sketch, photographs and a written description of the known requirements. Identify unresolved fields explicitly. A supplier may need clarification before offering a detailed quote; the reviewed build definition still needs approval before manufacture.

Does the drawing have to show every equipment-side part as a supplied item?

No. Mark parts that define the mating interface but are outside the supply scope as reference only. Keep their exact references visible so the cable-side configuration can be checked without inadvertently including them in the quote.

Can a sample replace the drawing?

A sample is useful evidence, but it does not explain every material, circuit assignment or permitted variation. Link the identified sample to the agreed documents and record any differences. Use the sample approval checklist to keep the physical build and the approved revision together.

Zeakka is a trading and sourcing partner. Send your drawing or marked sketch with its open questions so the project review can distinguish confirmed requirements from details that still need supplier and customer agreement. An email and a brief description are enough to begin; a completed drawing is not a condition for first contact.