Tube-type busbar shielding cylinder

A tube-type busbar shielding cylinder is a cylindrical insulating or shielding component designed to protect busbars from electrical flashover, interference, and mechanical damage while maintaining compact spacing in electrical panels.

Function and Purpose

Tube-type busbar shielding cylinders serve multiple purposes in electrical systems:

• Electrical insulation: They prevent accidental contact and flashover between busbars or to grounded surfaces, especially in high-voltage applications up to 72 kV (TE Raychem BBIT tubing) .
• Electromagnetic shielding: When used as a shielded cylinder, they reduce electromagnetic interference by positioning the shielding close to the busbar terminals, minimizing noise in sensitive circuits .
• Mechanical protection: Cylindrical insulators provide structural support and maintain spacing, ensuring stability under short-circuit forces or vibration .

Materials

Common materials for tube-type busbar shielding cylinders include:

• Heat-shrinkable polymers: Non-halogen polymers like TE Raychem BBIT tubing offer high dielectric strength, fire resistance, and shrink to fit both circular and rectangular busbars .
• DMC/BMC composites: Fiberglass-reinforced DMC/BMC insulators provide excellent dielectric strength, heat resistance, and dimensional stability, suitable for compact LV/HV assemblies .
• Metallic shields with insulating layers: Some designs integrate a conductive shield with an insulating outer cylinder to combine EMI protection with electrical insulation .

Design and Installation

• Cylindrical shape: Ensures uniform insulation and easy installation over busbars.
• Heat-shrinkable tubing: Applied using a gas torch, hot air, or oven, shrinking snugly over the busbar to achieve the required wall thickness .
• DMC cylindrical insulators: Available in various heights (25–75 mm) and diameters, often with brass inserts (M6–M12) for secure mounting .
• Shielded busbar systems: Can be mounted with brackets in control cabinets, allowing the shielding to be positioned close to terminals for optimal interference reduction .

Applications

Tube-type busbar shielding cylinders are widely used in:

• Switchgear and control panels: To reduce spacing requirements while maintaining safety and insulation .
• Power distribution systems: For high-current busbars where mechanical stability and insulation are critical .
• Sensitive electronic systems: Shielded cylinders minimize EMI in control cabinets, UPS systems, EV charging stations, and energy storage systems .

Advantages

• Compact design allows reduced air spacing between busbars.
• High dielectric strength and fire resistance improve safety.
• EMI shielding reduces interference in sensitive circuits.
• Easy installation and modularity for field or factory assembly. In summary, a tube-type busbar shielding cylinder combines insulation, mechanical support, and electromagnetic shielding in a cylindrical form, making it essential for safe, compact, and interference-free busbar installations in modern electrical systems.