IPC/WHMA-A-620 Class 1, 2 or 3 Selection Assessment
IPC/WHMA-A-620 defines acceptance criteria for cable and wire harness assemblies in three classes, and the class changes inspection effort, training and price. This assessment helps frame which class an application most likely needs before you quote or design.
1. What does the harness serve?
Pick the closest application type.
2. What happens if the harness fails in service?
3. Is uninterrupted performance required?
4. What is the operating environment?
5. What is the expected service life?
6. Can the harness be inspected or replaced after installation?
7. What does the customer contract or drawing require?
8. Does the product or customer require lot traceability and records?
9. What test and inspection depth does the application justify?
10. What cost trade-off is the customer willing to make for reliability?
How to use the assessment
Answer each question for the finished product the harness goes into, not for the harness in isolation. Score reflects the end-use consequences: safety, failure impact, environment, service life, and what the contract already says. The result is guidance. The final class is set by the customer or the product design authority, and the assessment helps you prepare a defensible conversation.
What the three classes mean
The standard describes Class 1 as general electronic products where the primary requirement is function of the completed assembly. Class 2 is dedicated service electronic products where continued performance and extended life are required and uninterrupted service is desired but not critical. Class 3 is high performance electronic products where continued high performance or performance on demand is critical, equipment downtime cannot be tolerated, and end-use environments may be harsh. Many requirements are common across classes, with tighter criteria at higher classes.
Reading the result
Treat a result near a band boundary as a prompt to ask the customer. If the contract states a class, that governs. If your result points higher than the contract states, raise it because later field failures can become your problem even when the drawing was silent. Remember that class is chosen for the acceptance criteria, and that a harness can meet a higher class without being required to.
Common mistakes
Assuming Class 2 by default without asking. Quoting Class 2 labor and then being held to Class 3 inspection. Applying one class to every harness in a mixed program when only some circuits are critical. Treating the class as a certification rather than an acceptance criterion applied by trained inspectors. Not stating the class on the traveler, which leaves operators guessing.
Frequently Asked Questions
Who decides which IPC/WHMA-A-620 class applies?
The customer or design authority decides, usually on the drawing or purchase order. The supplier should not choose a lower class on its own. If the class is not stated, ask in writing before quoting.
Is Class 3 always more expensive?
Generally yes, because tighter acceptance criteria require more inspection, stricter process control, more rework and documentation. How much depends on the design and the equipment. Quote each class on its own inspection and training assumptions.
Can one harness have more than one class?
Customers sometimes call out different classes for different circuits or features on a drawing. If so, state the mapping clearly on the traveler so operators and inspectors apply the right criteria to each.
Does this replace reading the standard?
No. This is a decision aid built on the standard's class definitions. Use the current revision of IPC/WHMA-A-620 for acceptance criteria and train inspectors to it.
If class, inspection plans and test records live on paper travelers, we can talk through carrying them as structured data in your ERP or quality system.
Related Tools
Wire Harness Build Checklist (IPC/WHMA-A-620)
A practical checklist for cable and harness builds covering materials, crimping, soldering, routing, marking and final test.
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Answer 8 questions about failure consequence, environment, and service life to see whether your product needs IPC Class 1, 2, or 3.
Compliance & ContractsWire Harness RFQ Review Checklist
Check the drawing package, BOM, class, test, material, compliance and commercial points on a harness RFQ before you commit to a price.
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A fill-in quote document for harness and cable assembly work: part and revision, workmanship class, price breaks, NRE, lead time, assumptions and signatures.
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- Wire Harness Quotation TemplateA fill-in quote document for harness and cable assembly work: part and revision, workmanship class, price breaks, NRE, lead time, assumptions and signatures.
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Guides
- IPC/WHMA-A-620 Requirements in a Wire Harness QuoteHow IPC/WHMA-A-620 Class 1, 2 and 3 affect harness cost: training, inspection, crimp validation, rework limits and what to state on the quote.
- ERP for Cable Assembly and Wire Harness Manufacturers: What to RequireWhat a cable assembly or wire harness shop needs from ERP: BOM by drawing revision, wire by the foot, lot traceability, kitting, and test records.
- How to Quote a Wire Harness From a Customer DrawingStep-by-step wire harness quoting: read the drawing, build the BOM, price wire and connectors, time every termination, and add NRE, test and scrap.
Manufacturing hubs
- WHMA and wire harness manufacturing: the A-620 standard, harness BOMs and the ERP problems that followWHMA and wire harness manufacturing: IPC/WHMA-A-620, crimp and cable assembly requirements, and the ERP, BOM and private AI issues harness shops face.
- IPC and its standards: what electronics manufacturers need to know, and the ERP and data work behind themIPC standards explained for electronics manufacturers: IPC-A-610, J-STD-001, IPC-6012 and IPC/WHMA-A-620, plus the ERP, traceability and private AI issues EMS shops face.