Ladder-type cable trays offer varying corrosion resistance depending on material and protective treatment, with options ranging from galvanized or high-resistance steel to aluminum, stainless steel, and fiberglass/GRP for harsh environments.

Metal Cable Trays

Steel Cable Trays: Standard steel trays are prone to corrosion when exposed to moisture, oxygen, and chemical agents. Protection is typically provided through hot-dip galvanizing (HDG), which immerses steel in molten zinc to form a sacrificial barrier, or through high-resistance (HR) coatings such as ZnAl, ZnMg, or ZnNi alloys, which offer improved durability and uniformity compared to HDG, especially for small parts and fasteners . According to IEC 61537, a cable tray is considered compliant if red rust covers less than 5% of the surface . Aluminum Cable Trays: Aluminum naturally forms a thin oxide layer (alumina) that protects against atmospheric corrosion. Aluminum trays are lightweight and resistant to many environmental agents, but they are electrically conductive and can experience galvanic corrosion when in contact with steel or stainless steel supports . Stainless Steel Cable Trays: Stainless steel, particularly AISI 316L, offers excellent resistance to chlorides and chemical attack due to its chromium and molybdenum content. It is highly durable in marine and industrial environments but comes with a higher initial cost .

Non-Metal Cable Trays

Fiberglass/GRP Cable Trays: Fiberglass-reinforced polymer (FRP) or glass-reinforced plastic (GRP) trays provide superior corrosion resistance because they do not undergo electrochemical reactions. They are non-conductive, do not require grounding, and resist acids, bases, and saltwater environments. While the installed cost is higher than painted steel, the lifecycle cost is lower due to extended maintenance and replacement cycles . GRP trays are widely used in chemical plants, oil and gas facilities, tunnels, and marine environments .

Summary

• Steel trays: Require galvanization or high-resistance coatings; suitable for general industrial use.
• Aluminum trays: Lightweight, corrosion-resistant, but may need isolation to prevent galvanic corrosion.
• Stainless steel trays: Excellent chemical and chloride resistance; high cost.
• Fiberglass/GRP trays: Non-corrosive, chemically resistant, electrically insulating; ideal for highly aggressive environments. Selecting the appropriate ladder-type cable tray depends on environmental exposure, chemical presence, electrical considerations, and lifecycle cost, with GRP and stainless steel being preferred for highly corrosive or marine conditions, while coated steel and aluminum are suitable for less aggressive environments.