When it comes to cable and wire harness assemblies, reliability isn’t optional — it’s essential. That’s why the electronics industry follows the IPC/WHMA-A-620 standard, the globally recognized guideline for how these assemblies should be built and inspected. Developed by IPC (Institute for Printed Circuits) and the WHMA (Wiring Harness Manufacturer’s Association), the standard defines the materials, methods and quality benchmarks manufacturers must meet to deliver consistent performance.

For engineers, buyers and quality managers, this standard provides assurance that assemblies will work as intended, whether inside everyday industrial equipment or in mission-critical systems for aerospace and medical devices. In this article, we’ll break down what IPC/WHMA-A-620 covers, how its classes are defined and why it matters when choosing a manufacturing partner.

Why is the IPC/WHMA-A-620 standard important?

The IPC/WHMA-A-620 standard provides a common language for cable and wire harness manufacturing. By clearly defining materials, workmanship and acceptance criteria, it helps ensure that assemblies are built consistently across different suppliers and industries. This consistency reduces misunderstandings, improves quality and gives buyers confidence that products will perform as expected.

For manufacturers, following the standard also streamlines training, inspection and documentation, making it easier to meet customer requirements and regulatory demands. In short, the standard matters because it protects end users, simplifies supplier relationships and sets a measurable benchmark for quality.

What does the IPC/WHMA-A-620 cover?

The IPC/WHMA-A-620 standard covers the materials, methods, testing and acceptance criteria for fabrication of all assembly activities. These activities include:

  • Cable and wire preparation
  • Wire stripping
  • Discrete wire termination
  • Soldering
  • Molding
  • Potting
  • Mechanical interconnections
  • Labeling
  • Testing

Together, the IPC cable assembly requirements give manufacturers and customers a clear benchmark for what quality workmanship should look like in every stage of cable and wire harness assembly.

What are the IPC/WHMA-A-620 classes?

In addition to defining materials and workmanship, the IPC/WHMA-A-620 standard also classifies assemblies into different quality levels, called classes. These classes ensure that each product is built to the right level of reliability for its intended application.

  • Class 1 – General Products: Everyday consumer items such as appliances, toys and simple electronics where basic functionality is sufficient.
  • Class 2 – Dedicated Service Products: Products that require extended performance and longer life, such as televisions, computers and communication devices.
  • Class 3 – High-Performance Products: Critical-use equipment designed for harsh environments, including medical devices, aerospace systems and military applications, where consistent performance is essential.

By assigning assemblies to these classes, the IPC/WHMA-A-620 standard helps manufacturers and buyers align performance expectations with the environments where the products will be used.

Who uses the IPC/WHMA-A-620 standard?

The IPC/WHMA-A-620 standard is used across industries where reliable cable and wire harness assemblies are essential. Engineers, buyers and quality managers rely on these wire harness manufacturing standards to ensure assemblies meet the performance and durability their applications demand.

Common industries include:

  • Automotive and transportation: For vehicle wiring and control systems
  • Industrial automation: For equipment, robotics and factory controls
  • Medical devices: Where patient safety depends on reliable connections
  • Aerospace and defense: For mission-critical systems in harsh environments
  • Consumer electronics: Where consistent performance is key to product life

Because it is widely recognized, the standard also helps suppliers and OEMs align expectations, making it easier to source and qualify assemblies from trusted manufacturing partners.

What does it mean to be IPC/WHMA-A-620 certified?

Being IPC/WHMA-A-620 certified means a manufacturer has trained personnel and documented processes that comply with the standard’s requirements. Certification demonstrates that a company can consistently produce cable and wire harness assemblies to recognized quality levels, whether Class 1, 2 or 3.

For customers, certification provides assurance that the supplier follows proven industry guidelines, reducing risk and improving reliability. For manufacturers, it signals credibility, streamlines audits, and often serves as a prerequisite for working with aerospace, defense, medical, or other high-reliability industries.

Building to the IPC/WHMA-A-620 standard with MJM Industries

Understanding the IPC/WHMA-A-620 standard is only the first step. Choosing a manufacturing partner who can apply it with precision is what ensures lasting performance.

At MJM Industries, our in-house engineering team and U.S.-based manufacturing capabilities deliver cable and wire harness assemblies that meet the requirements of IPC/WHMA-A-620, including Class 3 for the most demanding applications. Whether you need prototypes, low-to-medium volume production or ruggedized solutions for critical environments, we build with the quality and compliance you can trust.

Ready to ensure your assemblies meet IPC/WHMA-A-620 standards? Contact MJM Industries to discuss your project and learn how our team can deliver reliable, compliant solutions.