Standards are extremely important to OEM’s. A failed audit costs time and money. The Wiring Harness Manufacturer’s Association agrees and has created, with IPC, the ONLY industry-consensus international standard for the performance and acceptance of cable and wire harness assemblies, IPC/WHMA-A-620 Rev C, Requirements and Acceptance of Cable and Wire Harness Assemblies.

Why it is critical OEM’s should care about how wire harnesses are produced


Considered the “Nervous Systemof  the product

  • Distributes the electronic signals that are critical for product functionality
  • Design and assembly should provide long-term, mechanical, reliability for the application
  • Testing criteria takes assembly application into account

Can impact long-term reliability of the product

  • Durability/Warranty costs
  • Safety recalls
  • Reduced functionality
  • Intermittent electrical issues

Can reduce functionality of the product

  • Wires, components, connectors – most efficient?
  • Wires crimped too tightly or loosely
    • This can reduce functionality
“I have seen instances where an inspector will indicate that an assembly is acceptable, but that same assembly can be submitted to a different inspector who will reject it based on his own perception of what’s good and bad,” says Fahning. “Many times, drawings specify the components that go into an assembly, but they don’t tell you what is a good assembly or a bad assembly, or a marginally good or marginally bad one. The A-620 standard helps to differentiate variations that occur in normal processes. It eliminates opinions about what is good and what is bad.” ASSEMBLY

How the IPC/WHMA-A-620 standard can help ensure harnesses are constructed correctly



  • Assists engineering in the design of the harness
  • The workmanship standard is updated with the latest “best practices”


  • Creates consistent assembly processes


  • Defines acceptability criteria
    • For operators
    • Quality testing
    • Outsourced manufacturing partners
  • Helps eliminates variances among different manufacturing locations
    • Used in over 40 countries
    • Published in 12 languages
  • Easily understood by employees at all levels

Are you an OEM that builds harnesses?

  Learn More about A-620
“We feel as though the use of the IPC-WHMA-A-620 standards has become accepted lingo industry-wide,” Payton said. “It isn’t unusual now to see on prints a directive that would indicate to ‘Build according to IPC-WHMA-A-620 Standards’ instead of a long list of bullet points indicating specific directives.” WHMA Member