Standard tolerance for galvanized cable tray thickness

The typical steel thickness for galvanized cable trays ranges from 1.5 mm to 3 mm, with local zinc coating thickness not less than 45 µm and higher for heavier components.

Steel Thickness

Galvanized cable trays generally have side plates and base plates ranging from 1.5 mm to 3 mm in thickness, depending on the tray type and load requirements. Heavier components such as brackets and supports, which are often thicker than 3 mm, require stricter standards for coating and mechanical strength . The tolerance for steel thickness is usually defined by the manufacturer and should comply with relevant standards like IEC 61537 for metal cable trays .

Zinc Coating Thickness

The minimum local zinc thickness for standard tray sheets is 45 µm, corresponding to a coating mass of at least 325 g/m². For heavier components, the zinc thickness should be ≥55 µm to ensure adequate corrosion protection .

• Local Thickness: Measured at multiple points on the tray surface using a magnetic thickness gauge. Every point must meet the minimum requirement.
• Mean Coating Mass: Determined over the entire workpiece, often using gravimetric methods, to ensure uniform protection.

Tolerance Considerations

• The galvanized coating should be continuous, uniform, and smooth. Minor variations in color or passivation films are acceptable, but defects such as bare spots, blisters, rough nodules, or excessive zinc dross are not permitted .
• Electro-galvanized trays follow standards such as GB/T 26941.1-2011, which define acceptable tolerances for coating thickness and uniformity .

Summary

For standard galvanized cable trays:

• Steel thickness: 1.5–3 mm for base and side plates, thicker for brackets/supports.
• Minimum zinc coating: 45 µm for standard sheets, ≥55 µm for heavier components.
• Tolerance: All points must meet local thickness requirements; mean coating mass ensures overall uniformity.
• Appearance: Continuous and defect-free coating is required for functional integrity. These tolerances ensure mechanical strength, corrosion resistance, and compliance with international standards for safe and durable cable tray installations .