Fabrication of the inner arc of the cable tray

The inner arc of a cable tray is fabricated by carefully bending the tray material to the required radius while maintaining structural integrity and compliance with cable bend standards.

Material Selection

The first step is choosing the appropriate material for the cable tray. Common materials include steel, stainless steel, aluminum, and fiberglass. Steel and stainless steel are preferred for strength and durability, with stainless steel offering superior corrosion resistance, especially in moist or chemical environments.

Aluminum is lightweight and suitable for lighter cable loads, while fiberglass is ideal for outdoor or chemically aggressive environments (ElectricalEngineering123, ABB, ApexTray).

Cutting and Shaping

Before bending, the tray components—sides, base, and flanges—are cut to precise dimensions. Accurate cutting ensures smooth edges and proper alignment during bending. The pieces are then shaped into strips or sections ready for forming (ApexTray).

Bending the Inner Arc

To fabricate the inner arc: Determine the bend radius: The radius must comply with the minimum bend radius of the cables to prevent damage. Typically, the bend radius is at least 6 to 10 times the cable diameter, depending on cable type and insulation (ABB Technical Guide). Use appropriate bending tools: Mechanical or hydraulic benders are used for metal trays, while fiberglass trays may require heat-assisted forming or pultrusion techniques.

Form gradually: The tray is bent incrementally to avoid kinks, cracks, or deformation. For ladder or perforated trays, ensure rungs or perforations remain aligned and intact. Check structural integrity: After bending, inspect for stress points, cracks, or warping.

Reinforce if necessary with additional supports or welding.

Joining and Finishing

Once the inner arc is formed, the tray sections are welded or bolted together, depending on the material and design. Stainless steel may require TIG welding, while aluminum often uses mechanical fasteners. Finally, edges are deburred, and protective coatings (galvanization or powder coating) are applied to prevent corrosion (ApexTray, ABB).

Compliance and Standards

Ensure the fabricated inner arc meets NEMA VE1, VE2, or relevant national standards, including CE marking for European applications. Proper fabrication ensures safe cable routing, prevents overheating, and maintains mechanical support for the cables (SlideShare, Legrand). By following these steps, the inner arc of a cable tray can be fabricated safely, maintaining both mechanical strength and cable protection.