How are galvanized cable trays welded

Welding galvanized cable trays is generally not recommended on-site due to coating damage and corrosion risks; bolting or factory welding before galvanization is preferred.

Key Considerations

Galvanized steel cable trays are coated with zinc to protect against corrosion. Welding directly on galvanized surfaces can burn off the zinc coating, producing toxic fumes and leaving the steel exposed to corrosion. This makes on-site welding challenging and potentially unsafe.

Welding Procedures

Factory Welding: If welding is necessary, it is best performed before galvanization. This ensures the zinc coating remains intact on the rest of the tray, and the welded joints can be re-galvanized afterward.

On-

Site Welding: If unavoidable, proper ventilation and personal protective equipment (PPE) are essential to avoid inhaling zinc oxide fumes. After welding, the exposed steel should be treated with cold galvanizing spray or zinc-rich paint to restore corrosion protection. Techniques: TIG or MIG welding can be used for tack welding or small joints, but the thin gauge of cable trays often makes welding difficult and may deform the tray.

Alternatives to Welding

Bolting: The most common and recommended method for joining galvanized cable trays on-site. Bolting avoids coating damage and is easier to adjust during installation. Stud Welding: Specialized stud welding systems, such as powder-actuated or blunt-tip weld studs, can attach supports without compromising the tray's corrosion protection.

Safety and Compliance

Always follow local electrical and structural codes when joining cable trays. Ensure adequate ventilation when welding galvanized steel to prevent inhalation of zinc fumes. Consider pre-galvanized or hot-dip galvanized trays for environments where corrosion resistance is critical.

Summary

While welding galvanized cable trays is technically possible, it is preferable to avoid on-site welding due to corrosion and safety concerns. Factory welding before galvanization or bolting on-site are the recommended approaches to maintain structural integrity and corrosion protection.