How to use outdoor cable trays

Outdoor cable trays should be connected using proper splice plates, secure fasteners, and supports while ensuring alignment, grounding, and protection from environmental exposure.

Planning and Preparation

Before connecting trays, plan the route carefully, considering clearance, load capacity, and environmental exposure. Mark the path using a chalk line or laser level, and identify locations for bends, tees, or elevation changes. Ensure the area is free of obstructions and that supports can be installed at proper intervals, typically every 1.

5 to 2 meters, depending on tray type and load.

Selecting Materials

For outdoor installations, use corrosion-resistant trays such as aluminum, stainless steel, or fiberglass-reinforced plastic (FRP). Choose compatible splice plates, bolts, and brackets rated for outdoor conditions. Ensure all hardware is suitable for exposure to moisture, UV, and temperature variations.

Connecting Tray Sections

Align the trays end-to-end, ensuring the side rails and rungs are flush. Install splice plates across the joint. For metal trays, use carriage bolts or hex bolts with lock nuts, typically 3/8” or 1/4” depending on tray specifications.

Torque fasteners to the manufacturer's recommended values (e.g., 3/8” bolts to ~19 ft-lbs) to ensure a secure connection. Check alignment to prevent gaps or misalignment that could stress cables or reduce structural integrity.

Supporting the Trays

Use wall brackets, cantilever arms, or ceiling trapeze supports to hold the trays securely. Supports should be installed within 24 inches of each splice and at regular intervals along the tray length to prevent sagging. Ensure supports are anchored to structural members and not cut or weakened during installation.

Grounding and Bonding

Outdoor trays must be properly grounded to prevent electrical hazards. Use grounding straps or bonding jumpers across splice plates and along the tray system. Verify continuity of the grounding path after installation.

Finishing Steps

Deburr cut edges to prevent cable damage. Install covers if required to protect cables from weather or debris. Inspect the installation for secure fasteners, proper alignment, and adequate support before pulling cables.

By following these steps, outdoor cable trays can be connected safely, securely, and in compliance with electrical codes, ensuring long-term durability and protection for the cables.