Designing wiring harnesses is crucial across industries such as automotive, aerospace, and industrial machinery. A wiring harness comprises a bundle of wires, connectors, and other components used to transmit electrical signals and power within a system. To achieve reliable, cost-effective designs that meet performance standards, engineers must adhere to specific guidelines and best practices.
In this blog post, we explore the guidelines for designing wiring harnesses, focusing on the importance of planning, wire selection, routing, termination, and testing.
Why Good Wiring Harness Design Matters
A well-designed wiring harness is vital to the success of many industries. Benefits include:
Improved Reliability
Proper design enhances system reliability by ensuring wires and connectors are correctly routed, secured, and terminated, minimising the risk of electrical shorts, open circuits, and other faults.
Increased Durability
A well-designed harness is more resistant to wear and tear, as wires and connectors are protected from external forces such as vibration and abrasion.
Better Performance Customising harnesses to meet specific performance requirements helps optimise electrical pathways, reducing losses and maintaining signal integrity.
Cost Savings Effective design can reduce maintenance and repair costs by minimising wiring issues, leading to less downtime and increased productivity.
Compliance with Industry Standards Designing harnesses to comply with standards such as IPC/WHMA-A-620 ensures safety, reliability, and regulatory adherence.
Best Practices for Wiring Harness Design Designing a wiring harness requires careful consideration of multiple factors to ensure it meets both system and industry requirements. Engineers must aim for reliability, cost-effectiveness, ease of service, regulatory compliance, and well-documented manufacturing processes.
Factors to Consider Before Designing a Wiring Harness:
Electrical Performance The harness must meet the system's electrical requirements, including voltage, current, and signal integrity, with appropriate wire gauge, insulation, and shielding.
Environment Designs should account for environmental factors like temperature, humidity, vibration, and exposure to chemicals.
Durability Materials must be selected for wear resistance, impact resilience, and longevity in challenging conditions.
Serviceability The design should facilitate easy maintenance, with accessible wires, colour coding, and labelling for quick component replacement.
Manufacturing Harness designs should simplify the manufacturing process with standard, readily available components.
Cost Designs should balance performance with cost-effectiveness by selecting suitable materials and optimising the production process.
Connector Selection Choosing the right connectors is crucial for performance and reliability, factoring in the number of pins, mating cycles, and current capacity.
Wire Selection Selecting appropriate wire size, type, and insulation ensures the harness can handle electrical loads and environmental stress.
Routing and Placement Routing should minimise electrical losses and interference, while connector placement must allow easy access.
Termination Methods Termination techniques, such as soldering, crimping, or insulation displacement, should suit the wire and connector types while meeting performance standards.
Testing Comprehensive testing, including electrical and environmental assessments, ensures the harness meets required performance levels.
Safety Harnesses should be designed to mitigate risks of electrical shock, fire, and other safety hazards.
Electromagnetic Compatibility (EMC) Harnesses must be designed to minimise EMI and meet EMC regulations.
Assembly Design for assembly efficiency, using standardised components and connectors to streamline production.
Documentation Thorough documentation, including a bill of materials (BOM) and wiring diagrams, is essential for manufacturing, testing, and maintenance.
Conclusion Designing a wiring harness demands attention to detail and adherence to best practices. A well-designed harness ensures reliable performance, reduces failure risks, and cuts manufacturing and maintenance costs.
