Hot-dip galvanized cable trays typically require a steel thickness of 1.5–3 mm with a minimum zinc coating of 45 µm (325 g/m²), following GB/T 13912-2020 or equivalent standards.

Steel Sheet Thickness

The side plates and base plates of standard cable trays generally range from 1.5 mm to 3 mm in thickness, depending on the mechanical load and application environment. Heavier components, such as brackets and supports exceeding 3 mm, require higher coating standards to ensure corrosion resistance .

Zinc Coating Requirements

• Minimum Local Thickness: The zinc layer should be no less than 45 µm (corresponding to 325 g/m²) for standard trays. For thicker components, a minimum of 55 µm is recommended .
• Mean Coating Mass: This refers to the average zinc mass per unit area of the entire tray, which can be measured gravimetrically for quality control .
• Outdoor and Corrosive Environments: For trays exposed to marine or highly corrosive conditions, a coating mass of ≥275 g/m² (≈39 µm) is recommended as a cost-effective threshold to prevent rust during storage and transit .

Applicable Standards

• GB/T 13912-2020: Specifies hot-dip galvanized coatings on fabricated iron and steel articles, including local thickness, mean coating mass, and appearance requirements .
• ASTM A123/A123M: Defines zinc coating grades for hot-dip galvanized steel, commonly used in North America .
• NEMA VE-1 / IEC Equivalents: Used for metallic cable trays, ensuring mechanical strength, rigidity, and corrosion protection .

Additional Considerations

• Appearance: Coatings should be continuous, uniform, and free from defects such as bare spots, blisters, or excessive zinc dross .
• Repair: Any cuts or damaged areas must be repaired with compatible materials to maintain coating integrity .
• Electro-galvanized vs Hot-Dip: Hot-dip galvanizing provides superior corrosion resistance compared to electro-galvanized trays, especially for long-term outdoor or marine exposure . In summary, for compliance with national and international standards, hot-dip galvanized cable trays should use steel sheets of 1.5–3 mm thickness with a zinc coating of at least 45 µm (325 g/m²), increasing for heavier components or harsh environments, following GB/T 13912-2020, ASTM A123/A123M, or NEMA VE-1 standards .