Transformer, Busduct & Busway Flexible Links
Carsai manufactures custom flexible links for transformers, busducts, busway systems, switchgear and other high-current power-distribution equipment.
A flexible link creates an electrical connection while accommodating vibration, thermal expansion, installation tolerances and minor terminal misalignment. Compared with a completely rigid busbar, it helps reduce mechanical stress on transformer terminals, busduct joints and connected electrical components.
We manufacture each bus duct flexible link, transformer connector and busway jumper according to customer drawings, samples and operating requirements. Available constructions include multilayer copper foil busbars, braided copper connectors, flexible aluminum conductors, tinned terminal ends and insulated assemblies.
Customers can specify:
- Copper or aluminum material
- Continuous and peak current
- Flexible conductor cross-section
- Overall and flexible-section length
- Terminal dimensions
- Hole quantity and spacing
- Straight, bent or offset ends
- Tin, nickel or silver plating
- Insulation or protective sleeves
- Required movement and installation direction
For a broader overview of available structures, visit our Flexible Busbar Manufacturer page.
What Is a Busduct Flexible Link?
A busduct flexible link is a high-current conductor installed between busduct sections or between a busduct and another piece of electrical equipment.
It may connect a busduct to:
- A transformer
- Switchgear
- A switchboard
- A generator
- A circuit breaker
- A distribution panel
- Another busway section
- A power-conversion system
A rigid connection requires precise alignment between both terminal surfaces. A flexible link allows limited adjustment and helps accommodate movement caused by load changes and temperature variation.
Buyers may describe the same product using different phrases, including:
- bus duct flexible link
- busduct flexible link
- flexible link busduct
- flexible link for busduct
- busduct flexible bar
- busduct expansion connector
- flexible busduct connector
These terms generally refer to a flexible high-current conductor rather than the complete busduct system.
Why Busduct and Busway Systems Need Flexible Connections
Busducts carry high current through rigid copper or aluminum conductors enclosed inside a protective housing. As electrical load and ambient temperature change, the conductors and housing can expand or contract.
Mechanical movement can also result from:
- Building movement
- Transformer vibration
- Installation tolerances
- Equipment settlement
- Long busway runs
- Uneven mounting surfaces
- Thermal cycling
- Maintenance or component replacement
A flexible link placed at an appropriate connection point helps prevent these forces from being transferred directly to the electrical terminals.
It can also make installation easier when the busduct and equipment terminals are not perfectly aligned.
The flexible connector must still maintain sufficient electrical cross-section and contact area. Flexibility should never be achieved by reducing the conductor below the required current capacity.
Busway Flexible Link Designs
A busway flexible link performs a similar function in busway systems.
The term busway is commonly used for enclosed power-distribution systems containing copper or aluminum bars. Flexible links may be installed at equipment interfaces or expansion points.
Depending on the project, a flexible link busway design may use:
- Stacked copper foils
- Multilayer aluminum strips
- Copper braid
- Laminated conductors
- Flexible conductors with rigid end plates
- Insulated flexible busbars
The appropriate structure depends on the required current, movement, installation space and connection geometry.
For compact systems, a flat multilayer design may provide a lower profile. For installations requiring more movement in several directions, a braided connector may be more suitable.
Transformer Flexible Busbar Connections
A transformer flexible busbar connects transformer terminals to rigid busbars, busducts, switchboards or other electrical equipment.
Transformers can generate continuous vibration during operation. Their terminals may also move slightly because of thermal expansion and mechanical loading.
A rigid connection can transfer these forces directly to:
- Transformer bushings
- Terminal palms
- Busbar supports
- Insulators
- Switchgear terminals
- Busduct connection points
A flexible busbar for transformer applications helps isolate some of this mechanical stress.
Typical transformer connections include:
- Low-voltage winding to switchgear
- Transformer terminal to busduct
- Transformer terminal to busway
- Transformer to generator bus
- Rectifier transformer connection
- Furnace transformer connection
- Dry-type transformer terminal link
- Distribution transformer output connection
The terminal design must correspond precisely to the transformer drawing. Hole size, center distance, terminal width and phase spacing are particularly important.
Transformer Flexible Links and Jumpers
A transformer flexible link is usually a short conductor with flexible copper or aluminum in the center and solid mounting ends.
The phrase transformer flex link is also commonly used for the same product.
Depending on the installation, the link may be straight, bent or offset. The two ends do not need to have identical shapes.
Possible designs include:
- Flat straight links
- 90-degree terminal arrangements
- Z-shaped offsets
- Different terminal widths
- Unequal hole patterns
- Multiple-hole terminal pads
- One copper end and one aluminum transition end
- Braided copper with attached terminal plates
- Multilayer foil conductors with compressed ends
A transformer flexible jumper may bridge two terminals when a short flexible connection is required.
Similarly, buyers searching for a flexible jumper for transformer may need a multilayer or braided conductor that compensates for vibration and installation deviation.
The final construction should be selected according to the degree of movement and available space.
Multilayer Copper Flexible Links
Multilayer copper links are made by stacking several thin copper sheets or foils.
The end sections are compressed, welded, brazed or otherwise formed into solid terminals, while the center remains flexible.
This construction offers:
- High electrical conductivity
- Flat and compact geometry
- Controlled bending direction
- Large terminal contact surfaces
- Customizable layer quantity
- Precise terminal positioning
- Suitability for high-current applications
The layer thickness and quantity affect both current capacity and flexibility.
More thin layers generally provide greater flexibility than fewer thick layers with the same total cross-section.
However, the flexible section must also be long enough to accommodate the required movement. A very short multilayer section may remain relatively stiff even when thin copper layers are used.
Braided Copper Flexible Links
Braided copper links are manufactured from woven copper wires.
They are commonly selected when the connection requires:
- Greater softness
- Vibration absorption
- Movement in several directions
- Repeated mechanical movement
- Flexible installation routing
Braided links may use bare or tinned copper and can be supplied with:
- Pressed copper terminals
- Welded end plates
- Drilled mounting pads
- Copper lugs
- Custom-shaped connection ends
For transformer and busduct applications, braided links are often useful where vibration is greater or where the terminals cannot remain in a perfectly fixed position.
A multilayer foil link is generally flatter and more controlled, while copper braid normally offers greater overall flexibility.
Copper Versus Aluminum Flexible Links
Copper and aluminum may both be used for transformer, busduct and busway links.
Copper flexible links
Copper is commonly selected because it provides:
- High conductivity
- Compact conductor size
- Reliable terminal performance
- Good formability
- Compatibility with copper equipment terminals
Common copper grades include C11000, Cu-ETP and T2 copper.
Aluminum flexible links
Aluminum can reduce conductor weight and material cost.
It may be suitable when:
- The busduct conductors are aluminum
- The equipment terminals are designed for aluminum
- Weight reduction is important
- More installation space is available
- The complete joint system accounts for aluminum oxidation
Aluminum generally requires a larger conductor cross-section than copper for a similar current and temperature rise.
When copper and aluminum terminals are connected, the design should address galvanic corrosion and joint compatibility. A bimetallic transition piece, appropriate plating or another controlled interface may be required.
Current Capacity and Flexible Link Sizing
A transformer or busduct flexible link cannot be selected only according to a current label.
The required conductor cross-section depends on:
- Continuous current
- Peak current
- Short-circuit current
- Ambient temperature
- Enclosure temperature
- Ventilation
- Duty cycle
- Conductor length
- Installation orientation
- Allowable temperature rise
- Copper or aluminum grade
- Terminal contact resistance
High-current busduct systems may require links rated at 1600A, 2000A, 2500A, 3200A or higher.
A flexible link carrying 3200A must be evaluated as part of the actual assembly. The conductor cross-section, terminal contact area, bolt quantity and cooling conditions all affect operating temperature.
The terminals must be wide and thick enough to transfer current without excessive localized heating.
Terminal and Hole Design
Most busduct and transformer links are custom products because terminal layouts vary between equipment manufacturers.
Available options include:
- One-hole terminals
- Two-hole terminals
- Four-hole terminal palms
- Multiple-hole connection pads
- Round mounting holes
- Slotted holes
- Different hole patterns at each end
- Bent or offset terminal plates
- Different terminal widths
- Extended contact areas
- Attached copper or aluminum end plates
The drawing should specify:
- Hole diameter
- Hole center distance
- Terminal width
- Terminal thickness
- Phase-to-phase spacing
- Bend angle
- Mounting direction
- Flexible-section location
Terminal flatness is essential for a stable electrical connection. Burrs, distortion or uneven surfaces can reduce effective contact area and increase resistance.
Plating and Surface Treatment
Flexible copper links can be supplied bare or plated.
Tin plating
Tin plating is widely used for transformer and busduct connections because it provides corrosion protection and a consistent contact surface.
Plating can be applied to:
- Only the mounting terminals
- The complete flexible link
- Selected surfaces defined on the drawing
Nickel plating
Nickel plating may be considered for elevated-temperature or demanding environmental conditions.
Silver plating
Silver plating may be selected for particular high-current contact applications.
The plating type and thickness should be specified before quotation.
Aluminum terminal treatment requires a process suitable for the selected alloy. Joint preparation and protection should also be defined by the equipment designer.
Insulated Flexible Links
Flexible links can be supplied bare or insulated depending on the system voltage and available clearance.
Possible insulation options include:
- Heat-shrink tubing
- PVC sleeves
- Epoxy coating
- Powder coating
- Flexible protective covers
- Partial insulation
The terminal contact surfaces normally remain exposed.
The insulation design should identify:
- Covered conductor areas
- Exposed terminal areas
- Required voltage rating
- Insulation thickness
- Operating temperature
- Phase color
- Bend and movement zones
- Creepage and clearance requirements
Insulation should not prevent the conductor from moving within its intended range.
Manufacturing and Inspection
A typical production process includes:
- Reviewing equipment drawings
- Confirming material and current
- Determining the conductor structure
- Cutting copper or aluminum layers
- Stacking or preparing braided conductors
- Forming or attaching terminal ends
- Punching or machining mounting holes
- Producing required bends and offsets
- Deburring and cleaning
- Applying plating
- Adding insulation
- Performing dimensional inspection
- Protecting contact surfaces during packing
Key inspection items include:
- Overall length
- Flexible length
- Conductor width and thickness
- Hole size and spacing
- Terminal flatness
- Bend angle
- Plating coverage
- Insulation location
- Surface cleanliness
Information Needed for a Quotation
For an accurate quotation, please provide:
- Transformer, busduct or busway drawing
- Copper or aluminum material
- Continuous current
- Peak or short-circuit current
- Overall dimensions
- Flexible-section dimensions
- Terminal width and thickness
- Hole diameter and spacing
- Bend or offset requirements
- Required movement
- Plating type and thickness
- Insulation requirement
- Order quantity
- Annual demand
If the final drawing is unavailable, we can initially review a sketch, sample or installation photo.
Frequently Asked Questions
What is the difference between a busduct flexible link and an expansion joint?
A flexible link provides electrical continuity while accommodating limited movement. In some systems it can form part of an expansion connection, but the complete mechanical expansion-joint design may also include enclosure and support components.
Can one flexible link connect a transformer directly to a busduct?
Yes. The conductor can be customized to match the transformer terminal at one end and the busduct terminal at the other.
Can the two terminal ends have different hole patterns?
Yes. Each end can have a different width, hole quantity, spacing, bend or offset.
Which is more suitable: copper foil or copper braid?
Copper foil provides a flat profile and controlled bending. Copper braid is softer and better suited to vibration or movement in multiple directions.
Can aluminum busduct use copper flexible links?
Yes, but the copper-to-aluminum interface must be designed to prevent galvanic corrosion and maintain reliable electrical contact.
Can you manufacture high-current links for 3200A systems?
Yes. The final conductor cross-section and terminal design must be evaluated according to current, temperature rise, installation and cooling conditions.
Request a Transformer or Busduct Flexible Link Quotation
Carsai manufactures custom transformer flexible links, busduct connectors, busway links and high-current flexible jumpers for industrial power-distribution equipment.
Send your equipment drawing, current rating, required movement, terminal dimensions, hole pattern, plating, insulation and order quantity.
