Welding methods for ladder-type cable trays

Ladder-type cable trays are welded using either Cold Metal Transfer (CMT/GMAW) or TIG (GTAW) processes to attach rungs to side rails, ensuring structural integrity and compliance with electrical installation standards.

Welding Methods

Cold Metal Transfer (CMT/GMAW) is commonly used for welding ladder tray rungs to side rails. This method offers low distortion, high precision, and minimal spatter, making it suitable for light-gauge materials as thin as 0.3 mm. CMT welding is efficient for high-volume production and provides consistent, high-quality joints . Tungsten Inert Gas (TIG/GTAW) welding provides greater control over the weld, producing strong, smut-free, and splatter-free joints. TIG welding is ideal for applications requiring maximum weld quality, though it is slower and more difficult to master compared to CMT .

Material Considerations

Ladder trays are typically fabricated from steel, stainless steel, or aluminum, depending on environmental conditions and load requirements. Aluminum offers excellent corrosion resistance due to its natural oxide layer, while stainless steel (e.g., AISI 316L) provides high strength and resistance to corrosion, cracking, and pitting . The choice of material affects the welding process and parameters.

Design and Structural Factors

Ladder trays consist of two longitudinal side members connected by transverse rungs. Rung spacing commonly ranges from 150 mm (6") to 300 mm (12"), depending on cable type and load. The tray is usually supported every 2 to 6 meters, and the I-beam design of side rails provides 15–20% more strength than a C-shaped profile . Proper welding ensures the tray can safely support cable loads, including those generated during short circuits .

Standards and Safety

Welded ladder trays should comply with CSA, UL, and BS EN 61537 standards, ensuring mechanical strength, electrical safety, and durability. Installation should be performed by competent personnel familiar with electrical wiring and welding practices, and trays should not be used as walkways or for supporting personnel .

Best Practices

• Ensure clean, oxide-free surfaces before welding to improve joint quality.
• Select the welding process based on material thickness, production volume, and required weld strength.
• Maintain consistent rung spacing and alignment to prevent cable sagging or mechanical stress.
• Inspect welds for cracks, porosity, or incomplete fusion to ensure long-term reliability.
• Use appropriate protective coatings if trays are exposed to corrosive environments . By following these guidelines, welded ladder-type cable trays can provide durable, safe, and reliable support for electrical and communication cables in industrial and commercial installations.