Construction of galvanized cable trays in Tuvalu

Install galvanized cable trays by following approved shop drawings, preparing materials, setting supports, cutting and fixing trays, ensuring grounding, and applying corrosion protection.

1. Planning and Preparation

• Review Approved Shop Drawings: Confirm tray routes, lengths, bends, and clearances, ensuring no clashes with other services and maintaining horizontal and vertical runs .
• Material Inspection: Verify all galvanized trays, ladders, and fittings for compliance with specifications and check for damage. Remove unsuitable materials from the site .
• Environmental Consideration: In Tuvalu's humid, coastal climate, ensure galvanized trays are protected from moisture and direct sunlight during storage to prevent premature corrosion .

2. Site Preparation

• Clean Installation Area: Ensure the area is free of debris and ready for MEP works .
• Mark Tray Routes: Use the approved drawings to mark horizontal and vertical paths, maintaining sufficient clearance for cable pulling and future maintenance .

3. Installing Supports

• Support Layout: Mark support positions and install threaded rods with metal plugs. Fix 'L' angles or slotted 'C' channels with nuts, maintaining a maximum spacing of 1.2 meters to prevent sagging .
• Support for Bends and Offsets: Provide additional supports at bends, branches, and offsets to maintain structural integrity .

4. Cutting and Fixing Trays

• Cut to Length: Use appropriate cutting tools to adjust tray lengths. Apply mushroom head screws to avoid cable insulation damage during pulling .
• Fixing Trays: Secure trays to supports using bolts sized according to load requirements. Ensure trays are level, horizontal, vertical, or parallel to building features .
• Joint and Accessory Installation: Install tees, elbows, reducers, and joints with support within 300 mm of connections. Maintain minimum bend radius for the largest cable .

5. Grounding and Corrosion Protection

• Earth Continuity: Install grounding strips at all joints and connect to the main earth bar .
• Edge Protection: Remove sharp edges and apply approved galvanized paint on cut edges to prevent rusting .

6. Clearance and Maintenance

• Spacing: Maintain at least 75 mm between trays and building structures for cable security and maintenance access .
• Expansion Joints: Provide expansion joints where trays pass through building expansion areas .
• Fire and Floor Penetrations: Use approved sleeves and seal with fire-resistant materials where trays pass through floors or fire barriers .

7. Testing and Quality Assurance

• Continuity Test: After installation, perform electrical continuity tests to ensure proper grounding and system integrity .
• Inspection: QA/QC inspectors should verify compliance with approved procedures, installation standards, and documentation . By following these steps, galvanized cable trays in Tuvalu can be installed safely, efficiently, and with long-term durability against the tropical, coastal environment.