Thickness requirements for galvanized cable trays

Galvanized cable trays typically use sheet metal thicknesses from 1.2mm to 3.0mm, with zinc coating thicknesses ranging from 12µm for electro-galvanized trays to 45–55µm for hot-dip galvanized trays.

Sheet Metal Thickness

The sheet metal thickness of cable trays depends on the tray type, load capacity, and support spacing:

• Ladder Cable Trays: Designed for heavy power cables over long spans, recommended thickness is 2.0mm to 3.0mm to prevent side-rail deflection and rung deformation under load .
• Perforated Cable Trays: Balance weight and strength, typically 1.2mm to 2.0mm, ensuring cross-sectional stability for standard routing .
• Solid Bottom Trunking & Raceways: Used for sensitive signal lines requiring shielding, usually 1.5mm to 2.0mm to maintain flat tracking profiles . The thickness selection also considers support spacing: wider spans increase bending stress, requiring thicker side rails and deeper profiles to meet NEMA deflection criteria .

Zinc Coating Standards

Galvanization protects steel from corrosion, and the zinc coating thickness varies by galvanization method:

• Hot-Dip Galvanized (HDG) Trays:
  • Side and base plates (1.5–3mm thick) require a minimum local zinc thickness of 45µm (≈325 g/m² coating mass).
  • Heavier components (>3mm) require ≥55µm for adequate corrosion resistance .
  • Coating must be continuous, uniform, and free of defects like bare spots or blisters .
• Electro-Galvanized Trays:
  • Minimum zinc thickness is 12µm, suitable mainly for dry indoor environments due to limited corrosion resistance .

Key Considerations

• Environmental Conditions: Thicker coatings and heavier gauge steel are recommended for outdoor or corrosive environments to extend service life .
• Mechanical Strength: Trays must support cable weight plus a 20% spare load, with maximum horizontal support spacing of 1.5–6 meters depending on installation type .
• Inspection: Local thickness is measured at multiple points using a magnetic thickness gauge, while mean coating mass can be verified gravimetrically . Selecting the correct sheet thickness and zinc coating ensures structural integrity, corrosion protection, and compliance with standards such as NEMA VE-1, IEC equivalents, and GB/T 26941.1-2011 for electro-galvanized trays .