An order that says only “build to IPC” leaves important questions unanswered. Which document and revision apply? Who selects the product class? Which inspections happen before coverings conceal the connections? What evidence must accompany the shipment? Different answers can produce different quotations and acceptance decisions for the same drawing.
IPC/WHMA-A-620 for buyers is therefore a requirements-definition task, not simply a phrase to add to a purchase order. This guide explains how to establish an agreed workmanship baseline and connect it to drawings, supplier controls and release records. It does not reproduce the standard’s acceptance criteria or replace access to the licensed governing edition.
Define the Revision and Class Before Requesting a Quote
Separate current publication from contractual applicability
The official IPC/WHMA-A-620F public contents document identifies revision F, dated October 2025, as superseding revision E. It also explains that adopting a newer revision within an existing customer-supplier relationship is not automatic unless the contract requires it. Check publication status when establishing a new requirement, then state the agreed edition explicitly.
A useful purchasing entry contains the full standard designation, revision, applicable amendments or addenda, selected class and any approved exceptions. Do not use “latest revision” when the parties actually intend a frozen baseline: that wording can introduce an uncontrolled change during a long-running project.
For an existing order, compare the proposed revision change against current instructions, inspection criteria, training and accepted samples. Identify affected operations and obtain authorization before changing the baseline. Keep the old and new effective lots distinguishable, especially when inventory from both configurations will remain in service.
Have the responsible customer select the class
IPC/WHMA-A-620 uses product classes, but the applicable class should come from the customer’s approved requirements. Do not select it from a sales description, vehicle category or assumption that a higher class automatically makes every design suitable for its environment. Consult the class definitions in the agreed edition and record who approved the selection.
Class selection does not establish current capacity, ingress protection, vibration endurance or communication performance. Those requirements still need their own design and validation evidence. A well-inspected harness can remain unsuitable for its installed load or routing if the design inputs were incomplete.
Ask the supplier whether the quotation includes the selected class, required inspection access and record package. If a requirement cannot be met, identify the deviation before sample approval rather than presenting an unexplained exception at receiving inspection.
Connect Workmanship Criteria to the Complete Product Definition
Establish document precedence and resolve conflicts
Build a controlled requirement set containing the purchase specification, drawing, BOM, circuit map, component application instructions and agreed standard reference. Establish the document-precedence arrangement with the design owner and supplier. Do not assume that whichever document gives the easier result takes priority.
When a drawing and component instruction disagree about a termination feature, record the exact conflict, affected part combination and proposed resolution. The authorized technical owner should determine the applicable requirement. A supplier’s successful trial is evidence for review, not permission to disregard a controlled requirement.
The wire harness manufacturing process guide shows how document review connects to material issue, preparation, termination and final test. For acceptance planning, that connection matters because an inspection criterion must reach the operation where the feature is created and remains accessible.
Separate four different kinds of evidence
Workmanship inspection examines assembly features against the agreed criteria. Process verification establishes whether the selected materials, tools and settings create the intended connection. Electrical testing checks defined circuit behavior under specified conditions. Application validation checks whether the assembly performs in its intended installation.
These activities overlap, but they are not interchangeable. A continuity pass cannot establish adequate terminal retention. An attractive crimp cannot demonstrate loaded voltage drop. A supplier training certificate cannot establish that the shipped configuration matches the approved sample. Assign responsibility and acceptance sources for each activity.
| Requirement area | Buyer input | Evidence to request |
|---|---|---|
| Workmanship baseline | Standard, revision and class | Controlled criteria and inspector authorization |
| Product configuration | Drawing, BOM and circuit revisions | Material and assembly identity |
| Termination system | Wire, terminal and approved tooling | Setup and required verification records |
| Electrical behavior | Test scope, conditions and limits | Approved program and unit or lot results |
| Installed performance | Loads, environment and routing | Project validation and disposition |
| Delivery release | Record package and packaging rules | Authorized release and traceability |
For crimp-related requirements, the crimp pull-force testing guide provides additional planning context. Select the actual force limits, measurement conditions and complementary inspections from governing product documents; do not turn a general article into the acceptance authority.
Make the Inspection Plan Usable on the Shop Floor
Inspect concealed features at the correct stage
List the connections that will become inaccessible after assembly: splices beneath tape, terminals inside backshells, joints beneath heat shrink and conductors inside overmolds. Define the required inspection before concealment. Record enough identity to connect the inspection to the affected assembly or lot.
Access and visibility affect inspection planning. Specify appropriate lighting, magnification and handling through the governing criteria and approved procedure. Images should show orientation and the relevant feature clearly, but photographs are not automatically an adequate replacement for a required measurement or direct examination.
For uncommon constructions, obtain an approved engineering decision when the governing criteria do not directly address the feature. Do not force a specialized connection into an unrelated illustration simply because both contain wire and metal. Retain the decision with its scope and effective revision.
Define sampling and reaction rules
The inspection plan should identify inspection frequency, sampling basis, lot definition and escalation conditions. Sample quantities depend on the contract, process risk and approved quality plan; this guide does not prescribe a universal number. Establish first-piece, changeover and restart checks where required.
State what happens when a sample fails. The reaction may include stopping the operation, identifying material since the last demonstrated acceptable condition, expanding inspection or reviewing tooling. Assign the decision authority. A sampling plan without a reaction rule can identify defects without preventing affected material from moving forward.
Preserve original findings when reinspection or rework occurs. Define when a result is invalid because of an inspection setup problem, and distinguish that situation from a genuine product defect. Repeating a check until it passes does not provide a defensible disposition.
Match electrical test records to the circuit baseline
Require the approved test-program and fixture identities, the circuit-map revision and the intended fault coverage. Define which results are recorded per unit and which belong to setup or lot verification. Use independent review to avoid approving a tester with the same cavity-mapping error as the assembly instruction.
The harness continuity testing guide distinguishes opens, shorts and miswires from other electrical performance questions. Insulation resistance, dielectric withstand, loaded measurements or functional tests should be included only where the product requirements or approved plan call for them. Identify sensitive electronics before applying any potentially damaging test.
Review Supplier Claims and Control Nonconforming Material
Ask what each qualification statement actually proves
Separate individual training, organizational process recognition and product acceptance. Request the issuing body, scope, revision, holder, validity and relevant manufacturing site for any qualification claim. Verify what the document covers rather than treating a logo or certificate title as proof of the complete order.
A trained inspector still needs the correct criteria, product documents and measurement method. A recognized manufacturing scope does not automatically cover every material combination or installation. Ask how personnel are authorized for the actual operations and how proficiency is maintained when tools, processes or requirements change.
During supplier review, trace one selected requirement through the process flow, control plan, work instruction and inspection record. The custom wire harness sourcing guide supports this broader discussion. Examine actual evidence from the proposed route where available, not only a presentation assembled for the audit.
Keep defect disposition separate from commercial pressure
Define who may authorize rework, repair, concession and scrap. State which conditions require customer approval and what verification follows the authorized action. A delivery deadline does not change an acceptance criterion, and a concession for one lot should not silently become the normal production method.
Containment should follow evidence about the affected process and traceability boundary. If a terminal setup is found incorrect, investigate the relevant work in progress and completed material rather than assuming the last visibly inspected unit limits the problem. Document why the chosen boundary is justified.
For recurring findings, review the originating operation, component combination, tooling condition and instruction clarity. Correct the cause and verify effectiveness over an approved follow-up period or build scope. Closing an action solely because replacement parts passed does not establish that the original mechanism has been removed.
Use a Buyer Acceptance Record and Release the Correct Scope
The following fields can be copied into a purchasing or sample-approval record. They organize the decision; they are not substitute acceptance criteria. Attach controlled evidence instead of entering a general “IPC compliant” statement in every field.
| Record field | Required entry |
|---|---|
| Assembly identity | Part number, revision, lot and sample identifiers |
| Standard baseline | Full designation, revision, class and agreed addenda |
| Requirement authority | Customer specification and document-precedence approval |
| Component combination | Wire, terminals, housings, seals and approved sources |
| Inspection plan | Stages, sampling basis, access and reaction rules |
| Process verification | Tool identities, setup references and required results |
| Electrical evidence | Program, fixture, conditions, acceptance source and results |
| Exceptions | Deviation, scope, owner, expiry and approval |
| Disposition | Accepted, rejected or restricted approval with justification |
| Release authorization | Approver, date and permitted production scope |
Sample acceptance should identify exactly what was approved. Record whether the sample represents a development configuration or production-intent materials, tools and route. Changes to a terminal source, wire construction, applicator or test program may affect the evidence supporting approval and need review before use.
Receiving personnel also need access to the baseline and agreed records. Confirm labels, revisions, lot identity and required documentation before installation. If a record is missing or contradicts the delivered configuration, hold the affected decision for review instead of replacing the missing evidence with a supplier assurance.
Discuss your drawing, circuit map, intended class, inspection expectations and record requirements through TONFUL’s project enquiry channel. Ask for a documented review of applicability, open requirements and proposed verification before authorizing the build. Confirm project-specific capabilities and any qualification claims against their actual scope.