Latest Thickness Standard for Cable Trays

The latest international standard for cable tray thickness is defined in IEC 61537:2023, with specific thickness requirements varying by tray type, duty class, and material.

IEC 61537:2023 Overview

IEC 61537:2023 specifies requirements and tests for cable tray and ladder systems used to support electrical and communication cables. This edition updates the 2006 standard and includes technical revisions relevant to mechanical strength, load capacity, and safety, including the use of trays as protective earth conductors . While the standard does not prescribe a single thickness for all trays, it defines minimum mechanical and structural requirements that indirectly determine the necessary material thickness based on tray type and load.

Typical Material Thickness by Tray Type

Material thickness directly affects load capacity, allowable span, and long-term durability. Standard thickness ranges vary depending on the tray design and duty class :

• Ladder Trays: Designed for heavy cable loads and long spans. Side rail height and material thickness are critical. Heavy-duty ladder trays typically require 2.5 mm or more for steel or galvanized steel to ensure maximum support and heat dissipation .
• Perforated (Trough) Trays: Provide continuous bottom support with ventilation openings. Thickness depends on load and span, generally ranging from 1.5 mm to 2.5 mm for medium to heavy-duty applications .
• Channel Trays: Compact systems for small cable quantities and short runs. Thickness is usually lower, around 1.2 mm to 2 mm, as these trays carry lighter loads .
• Wire Mesh (Basket) Trays: Load capacity is governed by wire diameter and support spacing. Wire thickness typically ranges from 2 mm to 4 mm, depending on the number of cables and span .

Factors Affecting Thickness Selection

1. Load Class: IEC 61537 defines light, medium, and heavy-duty classes. Heavier loads require thicker side rails and rungs.
2. Span Between Supports: Longer spans increase deflection; thicker material is required to maintain structural integrity.
3. Environmental Conditions: Corrosion-resistant coatings (e.g., galvanized steel) may require slightly thicker material to compensate for potential material loss over time.
4. Cable Type and Heat Dissipation: Power cables generate heat; ladder trays with thicker rails improve airflow and reduce stacking issues.

Regional Considerations

• NEC (USA): Article 392 specifies cable tray sizing and thickness requirements, often aligning with IEC standards for load and span.
• ASTM A653: For galvanized trays, thickness must meet corrosion resistance standards, which may influence minimum gauge selection .

Summary

While IEC 61537:2023 provides the framework for cable tray design, actual thickness depends on tray type, duty class, span, and material. Typical ranges are:

• Ladder: 2.5 mm+ for heavy-duty
• Perforated: 1.5–2.5 mm
• Channel: 1.2–2 mm
• Wire Mesh: 2–4 mm Selecting the correct thickness ensures compliance, structural integrity, and long-term durability of cable tray installations .