Cable tray hangers are sized based on tray width, load capacity, material, and span, following standards such as NEC, NEMA, and IEC 61537.

Hanger Sizing Principles

Cable tray hangers are designed to support the weight of the tray and its cables while maintaining structural integrity and compliance with electrical codes. The key factors influencing hanger size include:

• Tray Width and Depth: Wider or deeper trays require stronger or larger hangers to prevent sagging and maintain proper alignment .
• Load Capacity: Hangers must support the combined weight of the tray, cables, and any additional equipment. Ladder trays carrying heavy power cables need more robust hangers than shallow wire mesh trays .
• Material and Thickness: Hangers are typically made of steel, stainless steel, or aluminum, with thickness selected to handle the expected load and environmental conditions .
• Span Between Hangers: Standard spans vary by tray type and load. For example, ladder trays may have spans of 1.5–3 meters, while lighter mesh trays can have longer spans with smaller hangers .

Standard Hanger Types

• Wall Brackets: Support trays along walls; size depends on tray width and load.
• Suspended Rods or Straps: Hang trays from ceilings; rod diameter and strap width are selected based on tray weight and span.
• Center Supports: Used for long tray runs to prevent sagging; size is determined by tray type and cable load .

Practical Sizing Guidelines

1. Determine Tray Load: Calculate the total weight of cables and tray per meter.
2. Select Hanger Material and Cross-Section: Choose steel or aluminum with sufficient thickness to handle the load.
3. Calculate Hanger Spacing: Use manufacturer recommendations or IEC 61537 guidelines to determine maximum spacing.
4. Check Compatibility: Ensure hangers fit the tray side rails and allow for thermal expansion and cable installation .

Example Specifications

• Ladder Tray (Heavy Load): Hanger rod diameter 10–12 mm, spacing 1.5–2 m.
• Perforated Tray (Medium Load): Steel strap 25–50 mm wide, spacing 2–3 m.
• Wire Mesh Tray (Light Load): Aluminum strap 20–30 mm wide, spacing 2.5–3.5 m .

Standards and Compliance

Cable tray hangers must comply with:

• NEC (National Electrical Code): Limits on cable fill and support spacing.
• NEMA VE 1: Guidelines for tray construction and support.
• IEC 61537: International standard for metallic cable tray systems, including mechanical strength, corrosion resistance, and installation compatibility . Proper hanger sizing ensures structural safety, code compliance, and long-term reliability of cable tray installations.