Welding for Trough-Type Cable Trays

Trough-type cable trays are secured using a combination of welding to support structures and bolted fasteners, ensuring mechanical stability, proper alignment, and electrical safety.

Welding to Support Structures

Trough-type cable trays are often mounted on MS (mild steel) support structures such as wall-mounted angles or C-channels. Welding is used to attach the tray supports or bridge structures to existing metal frameworks, particularly for long spans or heavy cable loads. The welding should be performed at regular intervals (e.g., every 1 meter) to maintain structural integrity and prevent sagging under load. After welding, the joints should be coated with primer and enamel paint to prevent corrosion and ensure a smooth finish .

Bolted Fastening

For connecting individual tray sections, high-tensile bolts, washers, and nuts are used. Typically, M8 bolts with coupler plates are employed to join two tray sections securely. Eight hardware sets per joint are recommended to ensure stability. Field drilling may be required to align holes for bolts, especially when using solid-bottom trays .

Hole Drilling and Brackets

• Field drilling is often necessary for drop-outs, pivot connectors, or when adjusting tray width. Standard hole sizes include 7/16” for solid bottoms and 5/16” for drop-outs .
• Shelf brackets, vertical pivot connectors, and horizontal pivot connectors are installed inside the tray to allow angular adjustments (up to 60°) and proper alignment with the support structure .
• Spring nuts and bolts are used to secure the tray to strut portions of hangers, providing flexibility and load distribution .

Cover and Accessory Fastening

Covers for trough trays can be secured using rivets, tek screws, or turnbuckles, depending on the design. Hold-down clamps or pre-mounted turnbuckles ensure that covers remain in place while allowing easy removal for maintenance .

Material and Corrosion Considerations

• Use galvanized steel, stainless steel, or aluminum depending on environmental conditions. Stainless steel (AISI 316L) is preferred for high corrosion resistance .
• After welding, repainting or enamel coating is essential to restore protective layers and prevent rust .
• Isolation pads (e.g., G-10 sheets) can be used at supports to electrically isolate the tray from the structure .

Summary

Proper installation of trough-type cable trays involves:

1. Welding support structures at regular intervals for stability.
2. Bolting tray sections with high-tensile hardware and coupler plates.
3. Field drilling for drop-outs, pivot connectors, and alignment adjustments.
4. Securing covers with clamps, screws, or turnbuckles.
5. Applying protective coatings after welding to prevent corrosion.

Following these practices ensures a mechanically robust, electrically safe, and maintainable cable tray system suitable for industrial and commercial installations .