Installation of Trough-type Fireproof Cable Trays

Proper installation of fireproof trough-type cable trays involves careful tray support, correct cable routing, and the use of firestop materials at penetrations to ensure safety and compliance.

Tray Selection and Material

Choose a trough-type cable tray made of galvanized steel, painted steel, or aluminum alloy depending on the environment. For indoor installations, painted or galvanized steel is common, while aluminum or stainless steel is preferred in corrosive or high-humidity areas. Ensure the tray width and thickness are sufficient to support the weight and number of cables without deformation.

Mechanical Installation

Support and Spacing: Install tray supports at intervals recommended by the manufacturer, typically using center hangers, spring nuts, and strut systems. Maintain a minimum of 12 inches (300 mm) clearance above and to the side of the tray for accessibility and maintenance. Mounting: Field-drill holes as needed for dropouts, brackets, and pivot connectors.

Use bolts and washers to secure the tray firmly, ensuring horizontal and vertical alignment. Routing: Plan the shortest and straightest path, avoiding unnecessary bends and crossings. Segregate power and signal cables to reduce electromagnetic interference.

Fireproofing Measures

Penetrations: When the tray passes through walls, slabs, or enters electrical panels, seal openings with firestop materials such as fire-rated boards, mineral wool, firestop packs, or intumescent caulks. Ensure gaps around cables do not exceed 1 cm² and packing thickness is at least 24 cm. Firestop Products: Use products like 3M Fire Barrier Moldable Putty+ or IC 15WB intumescent caulk to block heat and smoke penetration.

These can be applied to new installations or retrofitted in renovations. Encapsulation: For complete protection, cover cut edges of mats or trays with firestop caulk to prevent heat transfer to structural steel and cables.

Additional Considerations

Avoid installing trays in hoist ways or areas prone to physical damage. Ensure all structural building members remain intact; do not cut beams or supports. Maintain proper bend radii for cables exiting the tray to prevent damage.

Use solid or ventilated covers depending on heat generation and aesthetic requirements. By following these guidelines, a trough-type cable tray system can be installed safely, maintain accessibility, and provide effective fire protection for electrical installations.