Fixing of electrical cable trays and supports

Electrical cable trays are fixed using threaded rods, channel supports, and appropriate fasteners to securely attach the tray to ceilings, walls, or other structures while maintaining alignment and spacing.

Marking and Preparation

Before fixing, the path of the cable tray should be marked according to approved shop drawings, ensuring alignment from power distribution panels to designated endpoints. All bends, tees, and fittings should be prepared and of the same quality as the tray itself, forming a complete system before cable installation begins.

Support Methods

Cable trays are typically supported using GI threaded rods and slotted channel supports: For trays below 300 mm, 10 mm GI threaded rods are used; for trays above 300 mm, 12 mm rods are recommended. Threaded rods are fixed to the ceiling slab or wall using UNIFIX brackets, nuts, and washers.

G

I slotted C-channels (41 x 41 x 2 mm) are then mounted on the rods, providing a stable base for the cable tray.

Wall and Direct Fixing

When fixing trays or trunking directly to walls: Mark the wall for screw placement. Drill holes and insert screw fisher plugs. Affix the tray or trunking using self-tapping screws.

Sections are joined using fish plates or joiners to maintain continuity.

Alignment and Spacing

Each run of the tray must be leveled and aligned to prevent stress on cables. Adequate spacing should be maintained around trays for installation and maintenance access. Supports should be placed at intervals according to tray type and load, following national or local regulations.

Additional Considerations

Sharp edges should be ground before securing fittings. Fire stopping must be provided when trays pass through fire-rated walls. Cable trays can also serve as an equipment grounding conductor if properly bonded and electrically continuous.

By following these methods, cable trays are securely fixed, ensuring safe, organized, and code-compliant cable management in commercial and industrial installations.