Regulations for Galvanized Steel Strips for Cable Trays

Galvanized steel strips for cable trays must comply with international standards such as IEC 61537 and NEMA VE 1, with hot-dip galvanizing preferred for corrosion resistance and minimum zinc coating thickness specified by GB/T 13912-2020.

Galvanizing Processes and Standards

There are two main galvanizing methods for steel strips used in cable trays:

• Electro-galvanizing: Deposits a thin, uniform zinc layer via electrolysis. It provides moderate corrosion resistance and is specified under GB/T 26941.1-2011 for general cable tray requirements .
• Hot-dip galvanizing: Submerges steel in molten zinc, forming a thick zinc-iron alloy layer with superior adhesion and corrosion protection. This method is preferred for harsh environments such as outdoor, industrial, or coastal installations and is regulated by GB/T 13912-2020 .

Coating Thickness Requirements

• Tray sheet metal thickness 1.5–3 mm: Minimum zinc layer thickness of 45 µm (coating mass ≥ 325 g/m²).
• Heavier components (>3 mm): Minimum zinc thickness of 55 µm.
• For sea-freighted or coastal storage, a coating mass of at least 275 g/m² (≈39 µm) is recommended to prevent white rust and ensure long-term corrosion resistance .

Applicable Standards

• IEC 61537: International standard for metal cable tray systems, covering construction, mechanical performance, electrical continuity, and testing methods .
• NEMA VE 1: Specifies manufacturing requirements for metal cable trays in accordance with the National Electrical Code, including load/span designations and material specifications .
• SEC SDMS 06: For Saudi Arabia, metallic cable trays must comply with NEMA VE-1 or equivalent IEC standards, alongside local purchase order requirements .
• UL 568 and CSA C22.2: Cover performance and safety requirements for cable trays in North America .

Mechanical and Electrical Considerations

• Cable trays must meet mechanical load and deflection criteria as per IEC 61537, ensuring safe support of cables over specified spans .
• Electrical continuity: Trays used for grounding must have resistance <0.1 ohms across joints to safely carry fault currents .
• Material selection, galvanizing method, and coating thickness must align with environmental exposure, expected load, and project-specific requirements.

Best Practices

• Use hot-dip galvanized steel strips for outdoor or marine environments.
• Ensure uniform coating during manufacturing rather than post-fabrication galvanizing for consistent corrosion protection.
• Verify compliance with IEC 61537, NEMA VE 1, and local standards before procurement or installation.
• Consider higher coating mass for long-term storage or transport in humid or coastal conditions. By adhering to these regulations and standards, galvanized steel strips for cable trays will provide durable, safe, and corrosion-resistant support for electrical installations across diverse environments.