Fabrication of Upper and Lower Bow-Shaped Cable Trays

Bow-shaped cable trays are fabricated by bending metal or composite tray sections into smooth arcs to support cables while maintaining proper bend radius and structural integrity.

Materials and Selection

Bow-shaped cable trays are typically made from aluminum, galvanized steel, stainless steel, or fiber-reinforced plastic (FRP) depending on environmental conditions and load requirements . Aluminum offers lightweight construction and corrosion resistance, while stainless steel (e.g., AISI 316L) provides high strength and resistance to chlorides and industrial corrosion . Galvanized steel is cost-effective and suitable for indoor or mildly corrosive environments. FRP trays are used where chemical resistance and high strength-to-weight ratio are required .

Design Considerations

• Bend Radius: The curvature of the bow must respect the minimum bend radius of the cables to prevent insulation damage .
• Load Capacity: Determine the span and load class to ensure the tray supports the weight of cables without excessive deflection .
• Rung Spacing: For ladder-type trays, 6–9 inches (150–230 mm) spacing is recommended to support cables evenly .
• Ventilation: Open or perforated designs allow airflow to dissipate heat, while solid-bottom trays protect against dust or electromagnetic interference .

Fabrication Process

1. Cutting: Tray sections are cut to the required length using shears or laser cutting.
2. Bending: Sections are bent into the bow shape using press brakes, roll bending machines, or custom jigs. The bending process must maintain uniform curvature and avoid kinks.
3. Joining: Sections are joined using welds, bolts, or rivets, ensuring structural continuity and alignment.
4. Surface Treatment: Steel trays are often pre-galvanized or hot-dip galvanized; aluminum may be anodized for additional corrosion protection .
5. Inspection: Verify bend radius, alignment, and structural integrity before installation.

Installation Tips

• Support Spacing: Install supports at intervals recommended for the tray type and load to prevent sagging .
• Cable Management: Use cable ties or clamps to secure cables, maintaining minimum bend radius at entry and exit points.
• Modular Fittings: Bow-shaped trays can be integrated with straight sections, tees, and junctions for complex routing .
• Compliance: Ensure fabrication and installation comply with IEC 61537 and local electrical codes .

Summary

Fabricating upper and lower bow-shaped cable trays involves selecting appropriate materials, designing for load and bend radius, precise bending, joining, and surface treatment. Proper installation ensures cable protection, heat dissipation, and structural stability, making these trays suitable for industrial, commercial, and specialized electrical applications .