Busbar Solutions
Power Distribution is Becoming a Critical Design Consideration
Modern harsh-environment platforms across aerospace and defense applications are pushing the upper limits on power distribution. Higher voltage, tighter packaging, greater thermal load, and more complex integration requirements have spurred the need for busbars as a central part of the system architecture Higher operating voltages, increased power density, tighter packaging constraints, greater thermal demands, and increasingly complex system architectures are driving the adoption of advanced busbar solutions as a critical element of modern electrical systems.
Amphenol Commercial Air (ACAD) designs and develops custom busbar solutions for power conversion, distribution, propulsion, shielding, and connector integration within high-density, space-constrained platforms. Amphenol’s busbar solutions enable the efficient transfer of high current through compact, high-voltage systems while delivering the reliability and performance demanded by today’s aerospace and defense applications.
High-Voltage Busbar Solutions for High-Current Power Distribution
As aerospace and defense platforms demand greater electrical power and higher current densities, power distribution is increasingly influencing overall system architecture. Designers must move more power through systems that remain compact, lightweight, thermally efficient, mechanically robust, and serviceable throughout the life of the platform.
Rising current levels and increasingly constrained packaging can make traditional cabling difficult to incorporate. Larger, higher-current cables require greater bend radii and additional routing space, limiting flexibility within tightly integrated systems. Custom electrical busbars complement conventional cable and wiring assemblies by allowing the power path to be shaped around the system architecture, helping optimize space, simplify integration, manage thermal demands, and efficiently distribute high-current power through increasingly dense platforms.
What Is a Busbar? What Are They Used For?
A busbar is a high-current electrical conductor, typically made from copper or aluminum, used to efficiently distribute power between electrical components while reducing wiring complexity, resistance, and weight.. In its simplest form, an electrical busbar can be a flat bar, strip, plate, or rod. More advanced designs can include a laminated busbar, powder-coated busbar, flexible busbar, braided busbar, a printed circuit board (PCB) integrated busbar, or a fully integrated busbar assembly designed around the electrical, thermal, mechanical, and packaging requirements of the application.
Busbars are used wherever designers need a compact and efficient method to move power between sources, loads, circuits, connectors, and assemblies. By consolidating multiple current paths into a purpose-designed conductor, busbars can simplify system architecture and assembly, improve repeatability, and help manage voltage drop, thermal performance, and electromagnetic effects.
In harsh environment applications, busbars can become an integral part of the overall power architecture. High-voltage busbars may need to operate near sensitive electronics, fit within tightly constrained packaging envelopes, accommodate multiple connector interfaces, and maintain reliable performance under vibration, shock, temperature extremes, humidity, altitude, and demanding service-life requirements.
What Are Busbars Made Of?
The most common busbar material is copper or aluminum. Copper busbars are often selected when conductivity, current density, and compact packaging are priorities. An aluminum busbar may be used when weight reduction is a central design driver. In some systems, copper and aluminum can also be combined or joined when the design requires both conductivity and weight optimization.
Copper and aluminum are the most common materials used in busbar construction, with each offering distinct performance advantages. Copper busbars, including flexible busbar designs, are typically selected when high electrical conductivity, current-carrying capacity, and compact packaging are key priorities. Aluminum busbars provide a significant weight advantage compared with copper, making them an attractive option for applications where minimizing overall system weight is a key design priority. In certain applications, copper and aluminum may be combined or joined to balance electrical performance, weight, and overall system requirements.
A Variety of Busbar Options
Laminated Busbars
- Range of lamination materials for different temperature requirements, fluids, etc.
- Best performing at high voltages and altitude, including partial discharge mitigation
- Shielded busbars possible with this laminated technology
- Tooling required for laminating as well as forming
Advantages of Laminated Insulation
Laminated busbars use thin dielectric films bonded to one or more sides of the conductor. Common materials can include polyimide, polyester, PEN, PTFE/FEP-based films, and other application-specific dielectrics.
- Excellent dielectric performance in a thin, compact package
- Supports tight creepage and clearance requirements
- Well suited for complex multilayer and high-density designs
- Can provide repeatable, controlled insulation thickness
Powder-Coated Busbars
- Multiple off-the-shelf powder coating formulations available depending on performance needs
- Good fluid resistance
- High voltage capable
- Limited tooling required depending on geometry
- Low upfront cost/shorter lead times
- Best for prototype situations
Advantages of Power-Coated Insulation
Powder coating is done by applying a dielectric coating directly to the busbar surface, creating a durable insulating layer around the conductor.
- Durable and mechanically robust insulation
- Good resistance to abrasion, chemicals, moisture, and environmental exposure
- Can accommodate relatively complex busbar geometries
- Provides a continuous coating around exposed conductor surfaces
Overmolded Busbars
- Typically molded rubber, excellent sealing to surface of conductor
- Can be designed with an integral sealing feature and insulated fasteners
- Very good high-voltage performance at altitude
- Tooling required for molding process as well as forming
Advantages of Overmolded Insulation
Overmolding encapsulates the busbar within a molded polymer material, creating an integrated electrical and mechanical assembly.
- Provides excellent environmental protection and mechanical retention
- Enables complex three-dimensional geometries and integrated mounting features
- Well suited for highly integrated assemblies
Flexible Busbars
- Designed to accommodate tolerance stackups and improve routing
- Typically copper with a range of insulations for various performance levels
- Variable flexibility and pre-form geometries available
- Limited tooling required depending on design
Busbar Construction: Flexible Interconnect
| Solutions | Flex Busbar Images | Maximum conductor dimensions (thickness and/or width) |
Insulation | Flexibility | Stress on components | Advantages |
|---|---|---|---|---|---|---|
| Braided Busbars |
  |
Max cross-section: 240mm² |
In option | 3 axes | +++ | Can be part of a laminated busbar system; cost and flexibility (3 axes) |
| Ultra-Flexible Busbars |
  |
- Standard 0.8mm per layer; thicker conductors also possible - Possibility to stack several layers |
In option | - 2 axes - Up to 3 axes depending on the design |
++ | - Minimum stress on external components - Position gravity independent - Easy installation and better security |
| Thin Insulated Copper Conductors (Film) |  |
- Standard 0.8mm per layer; thicker conductors possible - Possibility to stack several layers |
Yes | - 2 axes - Up to 3 axes depending on the design |
+++ | Capability to combine conductors with different polarities |
| Press-Welded Busbar Used as Flex-Tab Connection |
  |
Max width: 100mm Max thickness: 10mm |
In option | 2 axes | +++ | - Can be part of a laminated busbar system - High current |
| Ultra-Flexible Cable Combined with PowerLug Technology |
  |
Custom development: Max cross-section: 240mm² |
Yes | 3 axes | +++ (depends on the cross-section) |
- Design flexibility - Possibility to integrate locking system - Can be used in high-humidity environments |
Picking the Right Insulation Material for Your Unique Design Considerations
Selecting the right insulation technology depends on the specific requirements of each busbar application. Lamination provides a thin, efficient package with strong dielectric performance; powder coating offers durable, economical surface protection; and overmolding provides a high level of mechanical and environmental integration. Depending on the application, busbars may also utilize thin-film laminates, wraps, edge sealing, or other application-specific insulation materials and processes.
For high-voltage power distribution, insulation selection and validation can be critical to long-term reliability. Testing may include insulation resistance and dielectric withstand testing, along with evaluation for potential defects or environmental effects such as pinholes, laminate cracks, moisture absorption, and contamination. Edge-sealing techniques can further enhance laminated designs by providing additional protection at the insulation interface in demanding operating environments.
The Right Electrical Busbar Configuration Depends on the Constraint
There is no single electrical busbar configuration that meets every power distribution requirement. Busbar construction should be selected based on the specific electrical, mechanical, thermal, and packaging demands of the application.
Key considerations include voltage and current requirements, available space, thermal management, mechanical tolerances, vibration and environmental exposure, manufacturing complexity, tooling economics, and connector integration. These factors influence the choice of conductor material, geometry, insulation technology, number of layers, and overall busbar construction.
Designed for Harsh-Environments and Mission-Critical Platforms
High-current busbars are among the most critical subsystems throughout the dense system architectures within modern harsh-environment applications. Electrical busbar systems are utilized throughout military aircraft, ground vehicle systems with microgrids, drones, missile systems, radar systems, directed energy weapon systems, commercial aircraft, eVTOL aircraft, satellites, and more. Each application presents unique electrical, mechanical, thermal, and environmental challenges that must be considered as part of the overall power distribution architecture.
Our engineers work closely with you and your team to address requirements such as vibration, shock, temperature, humidity, altitude, EMI, thermal management, connector integration, packaging, and long-term reliability.
By integrating these considerations into a purpose-designed current path, custom busbars can complement traditional cable and wiring solutions while helping optimize space, weight, performance, and system integration.
From concept through production, Amphenol Commercial Air works with you to develop custom busbar solutions engineered around the unique requirements of your platform. Contact us to discuss your next power distribution application.
Busbar Frequently Asked Questions (FAQ)
How do copper busbars and aluminum busbars compare?
Copper busbars offer excellent electrical conductivity and can support high current density in limited space. Aluminum busbars provide a lighter-weight alternative for applications where weight reduction is a primary design consideration. In some busbar designs, copper and aluminum may be combined to balance conductivity, weight, and system performance.
What types of busbars are available?
Common busbar types include rigid busbars, flexible busbars, braided busbars, laminated busbars, powder-coated busbars, and overmolded busbars. The right construction depends on current, voltage, thermal, mechanical, environmental, and installation constraints.
What is a high-voltage busbar?
A high-voltage busbar is designed to distribute electrical power safely and efficiently in systems with elevated voltage and current requirements. High-voltage busbar design may require specialized insulation, dielectric validation, thermal management, compact routing, shielding, and connector integration.
What is the difference between a rigid busbar and a flexible busbar?
A rigid busbar provides a fixed, formed current path for stable, tightly packaged installations. A flexible busbar, flex busbar, or braided busbar can accommodate movement, vibration, multi-axis routing, and difficult installation geometries while maintaining a high-current connection.
What is a flexible copper busbar?
A flexible copper busbar is a high-conductivity power interconnect designed to bend or accommodate movement within a system. Flexible copper busbars can be constructed using braided conductors, thin insulated copper conductors, press-welded flex tabs, or other application-specific configurations.
What is a laminated busbar?
A laminated busbar uses thin dielectric insulation films bonded to one or more sides of the conductor. This construction can provide a compact insulated package, strong dielectric performance, and the potential for shielding or multilayer power distribution in dense electrical systems.
What’s the difference between powder-coated and overmolded insulated busbars?
Powder-coated busbars use a dielectric coating applied directly to the conductor, providing durable surface insulation and accommodating relatively complex geometries. Overmolded busbars encapsulate the conductor in molded polymer material, creating a more integrated electrical and mechanical assembly.
Why is insulation resistance testing important for high-voltage busbars?
Insulation resistance testing helps verify that busbar insulation can withstand electrical stress and maintain separation between conductive paths. High-voltage busbar validation may also include dielectric withstand testing and evaluation for moisture absorption, contamination, pinholes, laminate cracks, and other insulation defects.
How are custom busbars designed for a power distribution application?
Custom busbar design begins with the platform’s voltage, current, available space, thermal requirements, mechanical tolerances, vibration exposure, environmental conditions, and connector interfaces. These inputs guide the selection of busbar material, geometry, insulation technology, number of layers, and manufacturing approach.
How are busbar connectors integrated into an electrical busbar system?
Busbar connectors can be integrated directly into a purpose-designed current path to reduce wiring complexity and improve packaging efficiency. Connector integration is considered alongside electrical performance, accessibility, mechanical retention, thermal behavior, and the overall architecture of the electrical busbar system.
Can a custom busbar replace traditional cable and wiring assemblies?
A custom electrical busbar does not necessarily replace every cable or wire assembly, but it can complement conventional wiring where high current, tight packaging, limited bend radius, repeatability, or routing complexity are concerns. Busbars can help optimize space, weight, integration, and power distribution performance.
Where are high-current power busbars used in aerospace and defense?
High-current power busbars are used across commercial aircraft, military fighters, military helicopters, unmanned and autonomous systems, drones, missile systems, ground vehicles with microgrids, phased-array radar, directed-energy systems, eVTOL aircraft, and satellites.
Can busbars be integrated with a PCB?
Yes. A PCB busbar or PCB-integrated busbar can be incorporated into a broader electrical assembly when power distribution, electronics, connectors, and packaging need to work together in a compact system. The feasibility depends on current requirements, thermal behavior, insulation, mechanical constraints, and system architecture. Contact your Amphenol representative for more information.
What information is needed to begin a custom busbar project?
Helpful starting information includes voltage and current requirements, space envelope, conductor material preference, thermal limits, insulation needs, connector requirements, mounting approach, environmental exposure, vibration and shock conditions, and expected production volume.
What types of applications are busbars typically used in?
Busbars are used in high-current power distribution applications that require compact, efficient, and reliable electrical power transfer, including:
- Commercial aircraft power distribution systems
- Military fighters and military helicopters
- Unmanned systems, autonomous systems, and autonomous drones
- Missile systems and other high-performance defense platforms
- Directed energy weapons (DEWs)
- Phased-array radar and other advanced radar systems
- eVTOL aircraft and other electric propulsion platforms
- Ground vehicles with microgrids and electrified power architectures
- Battery-powered systems, power conversion equipment, and high-voltage electrical systems
- Satellites and space vehicles
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