Method for fabricating inner bends in cable trays

Inner bends in cable trays can be fabricated by cutting, bending, and reinforcing the tray sections to achieve smooth directional changes while maintaining structural integrity.Materials and Tools RequiredTo fabricate inner bends, you typically need:Galvanized sheet metal (thickness per design, e.g., 1.6 mm)Measuring tape, marker, or scriberAngle grinder, metal shear, or hand fileDrill machine, rivets, or nuts & boltsBending tools (manual bender or hydraulic press brake)Welding machine (optional for reinforcement) For wire mesh trays, a bolt cutter can be used to make live bends on-site, with protective caps applied to cut ends to maintain safety and corrosion resistance .Step-by-Step Fabrication ProcessMarking the Bend Decide the bend angle (commonly 45° or 90°). Mark the centerline and sides of the tray. Divide the curve into equal segments to form a smooth radius .Cutting the Side Walls Cut triangular or rectangular sections on the side walls to allow bending. For flat bends, remove part of the tray lip and cut along the centerline carefully to prevent damage .Forming the Bend Gradually bend each segment using a manual bender or press brake. Ensure uniform bending to maintain cable support and tray integrity. For wire mesh trays, live bending can be done directly on-site .Rejoining and Reinforcement After bending, rejoin the cut sections using welding or bolting with metal strips. For flat 90° bends, a gusset can be cut and bolted to reinforce the bend .Measuring and Adjusting Measure the internal edges to ensure the bend radius is appropriate. While NEC does not specify a minimum radius for cable trays, manufacturers may provide recommended radii to prevent cable damage .ConsiderationsBend Radius: Pre-fabricated bends or field-fabricated bends can have different radii. Smooth curves reduce stress on cables and facilitate easier cable pulling .Tray Type: Ladder, solid-bottom, and wire mesh trays may require different cutting and bending techniques .Safety: Always wear protective equipment when cutting or grinding metal. Ensure edges are deburred to prevent cable damage .Field Fabrication: Many bends can be made live at the project site, especially for wire mesh trays, using bolt cutters and protective caps . By following these steps, inner bends in cable trays can be fabricated efficiently, ensuring both structural stability and safe cable routing.