Flexible insulated busbar consists of a stack thin copper sheets, which are laminated and bonded together to form a flexible, yet sturdy and durable conductor. The laminated copper sheets are wrapped by a highly flexible PVC or TPE insulation layer with extrusion technology.
The flexible insulated busbars are excellently suitable for high current connections in power distribution systems, particularly in automotive and renewable energy industries, due to their flexibility, light weight, and high current-carrying capacity. The flexible nature of the busbar allows for easy installation in tight spaces and around curves.
Technical data of flexible insulated busbars:
◼ Insulation:
➢ Material: high flexible PVC or TPE
➢ Color: PVC black or orange; TPE grey
➢ Thickness: 1.0~2.2mm
➢ Coating method: extrusion
➢ Dielectric strength: >23kV/mm
➢ Tensile strength: ≥20MPa
➢ Elongation after 135℃ 7-day aging test: >180%
➢ Oxygen index: 30%
➢ Flame retardant performance: self-extinguishing, UL94-V0
◼ Conductor:
➢ Annealed copper strips (≥99.9%Cu)
➢ Single layer thickness 0.3~1mm
➢ Surface: uncoated or tinned
➢ Electrical conductivity: ≥56.2MS/m (corresponding to ≥97%IACS)
➢ Tensile strength: ≥200MPa
➢ Elongation: ≥30%
◼ Working temperature:
➢ PVC: -30℃~+105℃
➢ TPE: -40℃~+135℃
◼ Operating voltage: 600Vac/750Vdc; 1000Vac/1500Vdc
◼ Voltage withstand performance with 15min / 50Hz AC:
➢ between busbar and ground: >15kV
➢ between busbars: >30kV
◼ Flame retardant performance: self-extinguishing, UL94-V0
◼ UL758 certificated
◼ SGS certified: RoHS compliant.
◼ Section area range: 7mm²~1200mm²
◼ Maximum size: 120x12mm
Main features of flexible insulated busbars:
◼ Easy assembly: it could be easily bended and fixed with hands or easy tools.
◼ Higher current-carrying capacity: due to conductor skin effect, the laminated busbar structure can achieve higher ampacity than solid busbars. Here is a comparison: 
◼ Possibility of reducing sizes of the equipment:
➢ Due to skin effect and favorable thermal radiation properties, the flexible insulated busbars can handle heavier current loads than solid busbars of the same cross-section.
➢ Due to good insulating performance of the PVC, it could be possible to reduce the distances between different flexible insulated busbars and between the flexible insulated busbars and earth.
➢ The bending-radius could be smaller than that of normal cable or solid copper bars, so that the connections could be more simple and short.
◼ Lower temperature-rise on the flexible insulated busbars than on normal copper bars.
◼ High flexibility: no problem with vibrations or thermal expansions.
Application of flexible insulated busbars:
The flexibility of the busbars makes it possible to install into difficult equipment or small places easily. They can be particularly well used as connectors in switchgears and between transformers, switching devices and prefabricated power networks.
Dimensions and ampacity:
◼ Standard length: 2m or 3m (25m in roll is possible for 1-layer busbars).
◼ Cross-section: up to 1200mmm².
◼ Ampacity: values in the table are only for reference, because the actual ampacity is related to the application conditions.
◼ We can produce pre-formed flexible insulated busbars according to customer drawings.
Guidance for selecting the correct dimensions:
The ampacities are related to the cross-sections and operating ambient temperature, as shown in above table. Therefore, three factors should be considered for deciding the dimensions:
➢ Ampacity
➢ Allowed temperature-rise on the flexibar
➢ Width of the flexibar
The temperature-rise △T can be calculated with formula:
△T=Tr – Ta
Ta: ambient temperature
Tr: temperature of busbars at rated current (pay attention: for general electrical apparatus, Tr should be ＜105℃).
Example (just for reference): If operating ambient temperature is 40℃, and you need ampacity 510A with bar width ＜ 40mm, you could get allowed highest temperature-rise 65K (105℃-40℃ =65K), so you could decide dimension 32×1×4. With this bar, the highest temperature-rise will be 50K with current 520A.
