If you manufacture, purchase, or inspect cable and wire harness assemblies, one standard governs the quality expectations for your entire supply chain: IPC/WHMA-A-620. Developed jointly by IPC and the Wire Harness Manufacturer's Association (WHMA), this standard is the only industry-consensus document defining requirements and acceptance criteria for cable and wire harness assemblies.
Whether your team calls it "IPC 620," "A-620," or "IPC/WHMA-A-620," it refers to the same standard — and understanding it is critical for anyone involved in harness design, manufacturing, or procurement. This guide covers everything you need to know: what the standard includes, how the three product classes work, what changed in the latest revision, and how to use A-620 to improve quality and reduce costs in your wire harness manufacturing projects.
Year the first edition of IPC/WHMA-A-620 was released
Current edition (2025), replacing Rev E from 2022
Product classes defining reliability requirements
Chapters covering all cable & harness workmanship topics
What Is IPC/WHMA-A-620?
IPC/WHMA-A-620 — formally titled "Requirements and Acceptance for Cable and Wire Harness Assemblies" — is the definitive industry standard for workmanship quality in cable and wire harness production. It describes the materials, methods, tests, and acceptance criteria for producing crimped, mechanically secured, and soldered interconnections in harness assemblies.
Think of it as the rulebook that both manufacturers and buyers use to agree on what "good" looks like. Without A-620, every manufacturer would set their own quality bar — making supplier comparisons, incoming inspections, and dispute resolution nearly impossible.
What IPC/WHMA-A-620 Covers (19 Chapters)
"I've audited over 200 wire harness suppliers across Asia and Europe. The single most reliable predictor of quality isn't the equipment on the factory floor — it's whether the operators can point to specific A-620 acceptance criteria for the work they're doing. Certified facilities have 60–70% fewer escaping defects than non-certified ones."
Hommer Zhao
Founder & Technical Expert, PCB Insider
The Three Product Classes Explained
IPC/WHMA-A-620 organizes all harness assemblies into three product classes. Each class defines progressively stricter workmanship requirements. The class your product falls into determines which acceptance criteria apply — and directly impacts manufacturing cost, inspection rigor, and supplier qualification requirements.
| Class | Name | Typical Applications | Inspection Level |
|---|---|---|---|
| Class 1 | General Electronic Products | Consumer electronics, toys, appliances, LED lighting | Basic visual inspection |
| Class 2 | Dedicated Service Products | Industrial controls, telecom, commercial equipment, automotive non-safety | Moderate inspection with sampling |
| Class 3 | High-Performance / High-Reliability | Medical life-support, aerospace, military, automotive safety-critical (ADAS, airbags) | 100% inspection, documented traceability |
* The product class is specified by the buyer (OEM) on the purchase order or assembly drawing. If no class is specified, Class 2 is the default per A-620.
How Classes Affect Acceptance Criteria
For every workmanship attribute — crimp height, solder fill, insulation clearance, wire dress — the standard defines four condition levels:
Target Condition
The ideal result. Preferred but not always achievable in production. Represents near-perfect workmanship.
Acceptable Condition
Meets all functional requirements. May not look perfect but is fully compliant with the specified class.
Process Indicator
Acceptable for Class 1 and sometimes Class 2, but flagged as requiring process improvement. Not a defect, but a signal to investigate.
Defect Condition
Fails the acceptance criteria for the specified class. Must be reworked or rejected — no disposition allowed without customer approval.
A condition that is "Acceptable" for Class 1 may be a "Process Indicator" for Class 2 and a "Defect" for Class 3. This is why specifying the correct class on your purchase order is critical — it directly controls the accept/reject boundary.
Key Workmanship Requirements in IPC/WHMA-A-620
The standard covers dozens of specific workmanship criteria. Here are the areas that cause the most quality issues — and where A-620 compliance delivers the greatest value.
Crimping Requirements
Crimping is the most common termination method in wire harnesses, and it is also the most frequent source of field failures when done incorrectly. A-620 defines detailed acceptance criteria for crimp height, crimp width, bellmouth, conductor visibility, insulation support, and pull-force (tensile) testing.
| Crimp Attribute | Class 1 | Class 2 | Class 3 |
|---|---|---|---|
| Conductor visibility at inspection window | Recommended | Required | Required |
| Bellmouth present on wire barrel | Not required | Required | Required |
| Insulation clearance gap | ≤ 2x wire insulation OD | ≤ 1x wire insulation OD | Per terminal spec |
| Pull-force (tensile) testing | Per sampling plan | Per sampling plan | 100% or per sampling plan |
| Crimp height monitoring | Periodic | Statistical process control | 100% monitoring or SPC |
Soldering Requirements
Soldered terminations in wire harnesses — particularly to turret terminals, cup terminals, and PCB pads — must meet A-620 criteria for solder fill, wetting, and joint appearance. Cold solder joints, excessive solder (bridging), disturbed joints, and insufficient wetting are all classified as defects across all three classes.
Solder must wet to both the conductor and the terminal — dewetted or non-wetted surfaces are defects
No cold or fractured solder joints — joints must show smooth, concave fillets
Flux residue must be cleaned per the process specification, especially for Class 3 assemblies
Solder shall not wick under insulation beyond the specified limit (prevents stiff stress risers)
Wire Preparation and Routing
Wire preparation — stripping, tinning, and forming — is the foundation of every termination. A-620 specifies that stripped wire ends must be free of nicks, cuts, or broken strands. For Class 3 assemblies, zero broken strands are permitted during stripping. The standard also defines minimum bend radii for routed cables to prevent conductor fatigue and insulation damage.
Defect Conditions
- Nicked, cut, or scraped conductor strands
- Insulation damage exposing conductor
- Strip length outside terminal specification
- Broken strands exceeding class limits
- Bird-caging (splayed strands) on stripped wire
Acceptable Conditions
- Clean strip with no insulation residue on conductor
- Strip length within terminal spec tolerance
- Strands intact and properly twisted (if required)
- Insulation end cut clean and square
- Tinning smooth and uniform (when specified)
"The most common mistake I see buyers make is not specifying the product class on their purchase order. Without a class callout, the manufacturer defaults to Class 2 — which may be over-kill for a consumer product (increasing your cost by 15–20%) or dangerously under-spec for a medical device. Always call out the class explicitly on every drawing and PO."
Hommer Zhao
Founder & Technical Expert, PCB Insider
What Changed in IPC/WHMA-A-620 Revision F (2025)
The latest edition — Revision F, released in 2025 — replaces Revision E (2022) and incorporates feedback from manufacturers, OEMs, and certification bodies worldwide. Here are the key updates that affect day-to-day manufacturing and inspection.
Strengthened Classification Guidance
Clearer rules for assigning product classes and handling mixed-class assemblies. Addresses the common scenario where a single harness contains both Class 2 and Class 3 circuits.
Updated Inspection Methodology
Refined visual inspection criteria with updated photographs and illustrations. Improved clarity on what constitutes a Process Indicator vs. a Defect for borderline conditions.
Enhanced Crimp Termination Criteria
More detailed acceptance requirements for stamped, formed, and machined contact crimps. Includes updated pull-force tables and crimp cross-section analysis guidelines.
Expanded Protective Covering Requirements
New criteria for heat shrink tubing, braided sleeving, conduit, and spiral wrap. Addresses modern materials not covered in previous editions.
Improved Process Control Requirements
Stronger emphasis on statistical process control (SPC) for critical parameters like crimp height and pull-force. Required for Class 3 and recommended for Class 2.
Updated Testing Section
Expanded guidance on electrical testing (continuity, insulation resistance, hipot) and mechanical testing (pull-force, flex-cycle) with clearer pass/fail criteria.
IPC/WHMA-A-620 vs IPC-A-610: What's the Difference?
These two standards are often confused because both deal with electronics assembly quality. The key distinction: A-620 covers cable and wire harness assemblies, while A-610 covers printed circuit board assemblies (PCBA). Many manufacturers need both certifications to cover their full scope of work.
| Attribute | IPC/WHMA-A-620 | IPC-A-610 |
|---|---|---|
| Scope | Cable & wire harness assemblies | Printed circuit board assemblies (PCBA) |
| Termination types | Crimp, solder to terminal, IDC, splice, ultrasonic weld | SMT, through-hole, BGA, press-fit |
| Product classes | Class 1, 2, 3 (same philosophy) | Class 1, 2, 3 (same philosophy) |
| Current edition | Revision F (2025) | Revision J (2024) |
| Co-developed with | WHMA (Wire Harness Manufacturer's Association) | IPC only |
| Typical users | Wire harness & cable assembly manufacturers | PCB assembly (SMT/THT) manufacturers |
* If your product includes both a wire harness and a PCB, both standards apply — A-620 for the harness portion, A-610 for the board assembly.
IPC/WHMA-A-620 Certification and Training
IPC offers a tiered certification program for A-620 that validates both individual competency and organizational capability. Understanding these tiers helps you evaluate supplier qualifications and invest in the right training for your own team.
Certified IPC Specialist (CIS)
For assembly operators, inspectors, and production supervisors. Covers hands-on application of A-620 criteria — identifying target, acceptable, process indicator, and defect conditions during production. Training typically takes 3–4 days.
Typical cost: $700–$1,500 per person
Certified IPC Trainer (CIT)
For quality engineers and training managers who need to certify others. CITs can train and certify CIS-level personnel within their organization. Requires passing a rigorous written and practical exam.
Typical cost: $1,500–$3,000 per person
Certified Standards Expert (CSE)
The highest certification level. For engineers and quality managers who need deep understanding of the standard for process development, supplier audits, and dispute resolution.
Typical cost: $2,000–$3,500 per person
Certification ROI
Industry data shows that IPC certification delivers 100–400% ROI in the first year through reduced rework, fewer customer returns, and improved first-pass yield. For most manufacturers, the investment pays for itself within 3–6 months.
"When we trained our entire production team to A-620 CIS level, our first-pass yield went from 91% to 97.5% within three months. The biggest improvement came from crimp quality — operators started catching borderline crimps during self-inspection instead of waiting for QC to flag them at end-of-line. The certification paid for itself in the first quarter."
Hommer Zhao
Founder & Technical Expert, PCB Insider
How to Use IPC/WHMA-A-620 When Sourcing Wire Harnesses
If you're a buyer or procurement engineer sourcing custom cable assemblies, A-620 gives you a powerful quality framework. Here's how to apply it effectively in your RFQ and supplier management process.
Specify the Class on Every Drawing and PO
Add 'Workmanship per IPC/WHMA-A-620, Class [1/2/3]' to your drawing notes and purchase order. This single line eliminates 80% of quality disputes.
Require Certified Operators
Ask suppliers to confirm that operators assembling your harnesses hold current CIS certifications. Certifications expire after 2 years — verify dates.
Define Inspection Sampling Plans
For Class 2, agree on AQL-based sampling plans for visual inspection and pull-force testing. For Class 3, expect 100% inspection with full documentation.
Use A-620 as the Dispute Resolution Framework
When quality issues arise, reference specific A-620 section numbers and figures. This removes subjectivity: either the crimp meets Figure 15-3 Class 2 Acceptable, or it doesn't.
Audit Against A-620 Requirements
During supplier audits, check that crimp height monitors are calibrated, pull-force testers have current certification, and operators can demonstrate correct inspection technique.
How to Choose the Right Product Class for Your Application
Choosing the wrong class wastes money (over-specification) or creates risk (under-specification). Use this decision framework to select the appropriate class.
| Question | Class 1 | Class 2 | Class 3 |
|---|---|---|---|
| Can the product be easily replaced? | Yes | With difficulty | No / life-critical |
| What's the consequence of failure? | Inconvenience | Service disruption | Safety hazard / mission failure |
| Expected service life? | 1–3 years | 5–10 years | 10–30+ years |
| Operating environment? | Indoor, controlled | Mixed, some harsh | Extreme (temp, vibration, chemicals) |
| Regulatory requirements? | Minimal | Industry-specific | Strict (FAA, FDA, MIL-STD) |
Frequently Asked Questions
What does IPC 620 stand for?
IPC/WHMA-A-620 is the standard number assigned by IPC (Association Connecting Electronics Industries) and WHMA (Wire Harness Manufacturer's Association). The 'A-620' designation indicates it's an acceptance standard. It's commonly shortened to 'IPC 620' or 'A-620' in industry conversation, but the full designation is IPC/WHMA-A-620.
What is the current version of IPC/WHMA-A-620?
Revision F, released in 2025, is the current edition. It replaces Revision E (2022) and includes updated criteria for classification, inspection methodology, crimp terminations, protective coverings, and testing. All previous revisions (A through E) are now obsolete.
What's the default class if none is specified?
Class 2 is the default when no product class is specified on the drawing or purchase order. However, relying on the default is poor practice — always specify the class explicitly to avoid cost overruns (if Class 2 is stricter than you need) or quality gaps (if you need Class 3).
How much does IPC 620 certification cost?
Individual certification costs range from $700–$1,500 for Certified IPC Specialist (CIS) to $2,000–$3,500 for Certified Standards Expert (CSE). Certifications are valid for 2 years. Industry data suggests ROI of 100–400% in the first year through reduced rework and improved yield.
Is IPC/WHMA-A-620 certification mandatory?
A-620 certification is not legally mandatory in most jurisdictions. However, many OEMs — particularly in automotive, aerospace, and medical — require their wire harness suppliers to hold current A-620 certifications as a contractual condition. In practice, uncertified manufacturers are excluded from most high-value supply chains.
How does IPC 620 relate to ISO 9001 and IATF 16949?
ISO 9001 and IATF 16949 are quality management system standards — they define how your quality system is organized. IPC/WHMA-A-620 is a product-level workmanship standard — it defines specific accept/reject criteria for harness assemblies. Most certified manufacturers hold both: a QMS certification (ISO/IATF) for the system and A-620 for the product workmanship.
References & Further Reading
[1] IPC/WHMA-A-620F — Requirements and Acceptance for Cable and Wire Harness Assemblies (2025 Edition), ANSI Blog — IPC/WHMA-A-620F Overview
[2] IPC/WHMA-A-620 Certification Programs, EPTAC — Mastering Quality Standards
[3] IPC/WHMA-A-620 Standard: Classes, Certification & Coverage, MJM Industries
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