A cable assembly is a group of wires or cables bundled together in a single unit and held together by a protective outer jacket. It usually contains two or more conductors wrapped in thermoplastics like polyurethane for protection against heat, vibration, and moisture.
This compact, durable bundle transits signal or power without the chaos of loose wires. This type of assembly is often used in systems that need reliability, organization and a long service life. Working with an experienced custom cable assembly manufacturer ensures your assemblies are engineered to specification and built following a proven cable assembly process for consistent quality and performance.
What does a Cable Assembly Include?
A cable assembly includes pars like conductors, insulation, shielding, jacketing, terminals, connectors, strain relief and cable ties.
- Conductors: These parts carry power, transmit a signal, or both. They’re wrapped inside the assembly and can be made of copper or aluminum, depending on what they’ll be used for.
- Insulation and Jacketing: Each individual wire is insulated, and then the entire unit is protected by an outer jacket made of thermoplastics.
- Shielding: Many cable assemblies use foil or braid shielding to prevent interference and shield the interior wires from EMI (electromagnetic interference).
- Connectors and Terminations: It may include a connector, plug, or socket at one or both ends.
- Strain Relief Components: These strengthen the cable assembly by protecting the wiring against wear & tear caused by movement, tension or vibration.
- Cable Ties or Sleeving: Cable ties or sleeves are an easy way to organize and bundle many wires into a neat structure.
How is a Wire Cable Assembly Different from a Wire Harness?
A wire cable assembly fully encases all wires or cables in a protective jacket, turning it into one unit. A wire harness leaves each wire exposed and still separate from each other.
The cable assembly is sealed, resistant to moisture, abrasion and vibration. It’s great for harsh environmental conditions. The wire harness is open, but it’s not protected, so it’s not the best choice for tough conditions.
Wire harnesses are often confused with cable assemblies and their names are often used interchangeably, but they’re not the same.
What Types of Cable Assemblies are there?
Cable assemblies come in various formats like coaxial, molded, ribbon, LED, USB, and circular. Each wire cable assembly is built to match specific electrical requirements, connector styles, and mechanical conditions.
Coaxial Cable Assembly
A coaxial cable assembly contains a central copper conductor (18 to 30 AWG), a dielectric core, braided shielding (up to 95% coverage), and a protective outer jacket. These are built to transmit signals in the GHz range, and use SMA, BNC, or N type connectors. They’re common in RF, broadcast, and satellite systems.
Molded Cable Assembly
A molded cable assembly permanently fuses the wires, cables, terminals, and strain reliefs into a single, sealed unit using PVC or TPE. The overmold supports IP67 sealing and protects against about 50 lbs of axial force. You can find these in field sensors, automotive, and wiring systems under vibration.
Ribbon Cable Assembly
A ribbon cable assembly holds up to 64 parallel electrical wires, often 28 to 30 AWG, in a flat bonded profile. These cables are encased and support IDC (insulation displacement type) terminals and 0.05 inch pitch headers. They’re used in backplanes, disk drives, and board interconnects.
LED Cable Assembly
An LED cable assembly includes two or more conductors (commonly 20 to 22 AWG) routed in PVC jackets and terminated with plug lock or screw terminals. It meets Class 2 power ratings and supports constant voltage LED drivers up to 60V. They’re often built for signage, displays, and automotive lighting.
USB Cable Assembly
A USB cable assembly includes twisted data pairs (28 AWG), 20 AWG power lines, foil/braid shielding, and molded USB A, USB-C, or Micro B ends. It must pass USB-IF standards for resistance (<0.25 ohm) and current draw (up to 3A). These assemblies are used to connect devices that need both data and power transfer.
Circular Connector Cable Assembly
A circular cable assembly uses M8 or M12-style connectors and meets IP65 to IP69K ratings. Cable jackets may be made from halogen free TPE or flame-retardant PVC. They’re common for industrial automation and motion control applications exposed to washdowns or shock loading.
Power Cable Assembly
A power cable assembly uses 12 to 4 AWG conductors wrapped in XLPE, EPDM, or rubber insulation. These assemblies must support loads ranging from 600V to 1kV and comply with UL 62 or UL 83 standards. Terminations may include ring lugs, compression lugs, or pin terminals for panel integration.
Flat Cable Assembly
A flat cable assembly may include ribbon-style bonded wires or laminated FFC/FFC with copper strips etched into PET. These are rated for bend radii down to 5 mm and over 10 million flex cycles, often seen in robotic arms or display hinges.
Custom Cable Assembly
A custom cable assembly is designed to perfectly match the client’s drawings. They can include almost anything, like hybrid signal/power routing, mixed cable or wire gauges, overmolding, and panel connectors. Custom cable assemblies are used when the regular off the shelf cables can’t handle the demands of the specific application, like medical carts, test rigs, EVs, and robotics.
Where are Cable Assemblies Used?
Cable assemblies are used across commercial, industrial, automotive, and medical systems; basically anywhere that needs to organize and protect electrical wires under load.
| Industry | Cable Assembly Type | Application Description |
|---|---|---|
| Automotive | Molded wire cable assembly. | Used in ignition, sensors, and battery modules to protect wires or cables from heat, vibration, and fuel exposure. Meets ISO 19642. |
| Industrial Control | Custom cable assembly. | Includes panel connectors, EMI shielding, and strain relief for PLCs, sensors, and drive controls. Built for UL 508A panels. |
| Medical | USB and ribbon cable assembly. | Connects ECGs, diagnostic displays, and imaging devices. Must pass IEC 60601 and withstand sterilization. |
| Telecommunications | Coaxial cable assembly. | Carries RF signals in routers and antennas. Requires 50 ohm impedance, <0.3 dB/m loss, and SMA/BNC terminations. |
| Aerospace | Circular cable assembly. | Supports cockpit instrumentation and seat systems. Jacketed with thermoplastics such as polyurethane to meet FAR 25.853. |
| Consumer Devices | Flat cable assembly. | Used in laptops, TVs, and mobile devices. Routes many wires and cables in thin profiles using FFC or ZIF connectors. |
| Robotics | Circular cable assembly. | Provides flex-life rated cabling for arms and joints. Uses 24 to 18 AWG conductors, rated for 10+ million cycles and IP68 sealed connectors. |
How is a Cable Assembly Manufactured?
A cable assembly is manufactured through six stages: design, material selection, cutting, termination, jacketing and testing. Each step ensures that the cable and wire system meets the functional, mechanical, and electrical requirements of the system.
1. Design and Engineering
The process begins with design drawings that specify things like routing, types of terminals, jacket dimensions, shielding layout, and component interfaces. Engineers use CAD software and generate a build sheet for harness production which also addresses like space constraints, EMI protection and load handling.
2. Material Selection
Engineers choose materials based on voltage class, routing conditions, and cable against wear and tear. Conductors are selected by gauge and electrical conductivity. Jackets may be made of PVC, XLPE, or thermoplastics, such as polyurethane, especially for cables being used in harsh environments. Shielding is chosen based on frequency, while connectors are matched to termination specs.
3. Cutting and Wire Preparation
Each wire is cut to exact length using automated cutters. Technicians program trip lengths, crimp locations and insulation clearances into the machinery for a streamlined flow. They also apply wire IDs for assembly accuracy.
4. Termination and Crimping
Terminals are attached using calibrated crimp tooling or soldering. These terminations define how the cable assembly or wire harness will connect to the external systems. Pull testing confirms the terminals’ strength and electrical continuity.
5. Routing, Jacketing, and Shielding
Conductors are routed through wiring looms or fixtures to match the layout drawings. Assemblies are bound with braided sleeving, heat shrink or overmolding. These features are built to shield the interior, prevent EMI intrusion, and protect from flex fatigue or abrasion.
6. Testing and Quality Inspection
All wire harnesses and cable assemblies are tested for continuity, high-voltage insulation resistance, and correct pin-to-pin wiring. Only high-quality cable assemblies pass these tests and can move out of the factory and to the client. Test data is logged to meet traceability and quality standards.
Each finished assembly is serialized and released only when it passes all inspection steps. This process ensures that every cable assembly is built to spec, durable and qualified for its intended electrical system.
What Tests are Performed on a Cable Assembly?
A cable assembly is tested for continuity, insulation resistance, high voltage handling, mechanical pull, and environmental sealing. Each test confirms that the cable and wire system meets its electrical and durability requirements.
1. Continuity Testing
This test confirms that current flows through each wire from end to end. All types of terminals are probed using automated test fixtures that flag open circuits, cross wires, or misroutes. Continuity testing must be performed on all cable assemblies.
2. Insulation Resistance Testing
Voltage is applied between conductors positioned next to each other to check insulation strength. Results are measured in megohms. Assemblies must meet the minimum clearance specs to avoid short circuits or arc faults in the field.
3. High-Pot Testing (Dielectric Withstand)
A high voltage surge (500V to 3000V) is applied between conductors and shielding to simulate worst-case breakdown conditions. If any voltage leaks through the insulation, the cable assembly fails.
4. Mechanical Testing
Assemblies may be pull tested at up to 50 pounds of axial force to verify crimp and terminal retention. Connectors are torque-checked, and jackets are inspected for deformation. These checks protect the cable against wear and tear in dynamic applications.
5. Environmental Testing
Some builds require thermal cycling, humidity exposure, or vibration testing. These simulate real-world environmental conditions, like outdoor use or in-vehicle motion. Overmolded cables that are encased must hold a seal under IP67/IP68 conditions.
What Standards Apply to Cable Assembly Manufacturing?
Cable assembly manufacturing must meet IPC/WHMA-A-620, UL 758, CSA 22.2, RoHS, REACH, AS9100 and TL 9000 standards. Each one defines how the cable and wire system is built, routed, tested, and approved for use.
- IPC/WHMA-A-620: Defines quality for wire harnesses and cable assemblies, including crimp integrity, conductor prep, and workmanship.
- UL 758: Regulates encased appliance cables, focusing on voltage, insulation, and flame resistance.
- CSA 22.2: Covers safety for Canadian cable and wire builds, including material specs and labeling.
- RoHS: Restricts hazardous substances in jackets, connectors and solders.
- REACH: Requires chemical disclosure and risk management across all materials.
- AS9100: Aerospace QMS for harness production, with an emphasis on traceability and process control.
- TL 9000: Telecom-focused QMS standard for cable assembly or wire harness systems in network infrastructure.
What Causes Wire Cable Assembly Failures?
Wire cable assembly failures are usually caused by mechanical stress, environmental exposure, installation errors or material degradation. Each failure compromises the bigger electrical system, interrupting the function of the cable and wire unit.
Mechanical Damage
- Bending: Tight bends, or constant bending, can cause wire strands to break.
- Abrasion: Friction against sharp surfaces wears through the protective outer layer.
- Tension: Excessive pull force can stretch or severe internal elements or weaken types of terminals.
- Vibration: Continuous motion may loosen crimps, fatigue solder joints, and fracture wires.
Environmental Factors
- Moisture: Water corrodes metal and causes short circuits inside cables.
- Temperature Extremes: Heat ruins insulation, and cold makes jackets brittle.
- Chemical Exposure: Solvents, oils and cleaning agents corrode jackets and connectors.
- UV Radiation: Prolonged sunlight cracks and weakens jacketing over time.
Installation Errors
- Improper Crimping: Weak crimp joints lead to high resistance and open circuits.
- Incorrect Gauge: Using an undersized wire causes overheating under load.
- Wrong Cable Type: Mismatched cable assembly or wire harness selections fail in high flex or high load conditions.
Other Factors
- Corrosion: Oxidation of conductors can damage contacts and break the electrical circuit.
- Overload: Exceeding the rated current leads to a high chance of damaging the insulation and wrapped conductors.
- Material Aging: Jackets and insulation degrade naturally over time, especially under thermal cycling.
- Poor Cable Management: If there’s no strain relief or if the routing is loose, it can stress the assembly during use.
- Manufacturing Defects: Flaws in harness production, like misaligned crimps or voids in the overmold, can cause early failure.
FAQs on What is a Cable Assembly?
What is the difference between a custom and standard cable assembly?
A custom cable assembly is built to match the specific routing, connector and performance requirements that the client asks for. A standard cable assembly follows predefined specs and dimensions used across general applications.
Custom cable assemblies support unique layouts, hybrid terminations or tight space constraints. Standard assemblies are cheaper and faster to get, but may not meet the specific needs of a complex electrical system.
How does length affect cable assembly performance?
Longer cable assemblies increase resistance, reduce signal strength, and raise voltage drop, which affects both power delivery and data integrity. Cables that are too long can also increase EMI exposure and strain on the electrical system.
How do you ensure signal integrity in cable assemblies?
We keep signal integrity in cable assemblies by using high quality shielding, impedance control, and proper conductor spacing. Foil or braid shielding blocks EMI. Controlled impedance prevents signal reflection. Shorter lengths and high quality crimp terminations reduce noise and loss in the electrical system.
What documentation typically accompanies a cable assembly order?
A cable assembly order includes technical drawings, wiring schematics, test reports, and material certifications. These documents confirm the cable and wire layout, types of terminals, test results, and compliance with the systems they’ll be used on.
Back to Top: What is a Cable Assembly? | Understanding Wire Assembly Types
