Welding of galvanized ladder-type cable trays

Welding galvanized ladder-type cable trays requires careful preparation and post-weld treatment to maintain corrosion protection and structural integrity.Key ConsiderationsGalvanized Coating: Galvanized steel cable trays are coated with zinc to protect against corrosion. Welding directly on galvanized surfaces can burn off the zinc layer, exposing bare steel to corrosion and producing toxic zinc fumes, which are hazardous if inhaled . Health and Safety: Welding galvanized steel generates zinc oxide fumes, which can cause metal fume fever. Proper ventilation, fume extraction, and personal protective equipment (PPE), including respirators, are essential . Welding Techniques:Spot welding or tack welding is often preferred for minor connections to minimize zinc loss.MIG or TIG welding can be used for structural joints, but the area around the weld must be cleaned of zinc coating to ensure proper fusion and reduce fume generation .Avoid excessive heat to prevent warping or weakening the tray structure. Post-Weld Treatment:After welding, reapply a zinc-rich paint or cold galvanizing compound to restore corrosion protection on exposed steel surfaces .Inspect welds for structural integrity and ensure that the tray maintains its load-bearing capacity according to standards like BS EN 61537 . Alternative Joining Methods:Mechanical fasteners (bolts, rivets) or swaged connections can be used to avoid welding altogether, preserving the galvanized coating and reducing health risks .Pre-galvanized or hot-dip galvanized trays can be cut and joined with splice plates instead of welding to maintain corrosion resistance . Standards and Compliance:Ensure that welding and installation comply with local and international standards for cable trays, including BS EN 61537 and ASTM specifications for galvanized steel .Only qualified personnel familiar with electrical installation practices and safety should perform welding on cable trays .SummaryWelding galvanized ladder-type cable trays is feasible but requires removing zinc at the weld site, using proper ventilation, and restoring corrosion protection afterward. Where possible, mechanical connections are preferred to maintain the integrity of the galvanized coating and reduce health hazards. Following standards and manufacturer guidelines ensures both safety and long-term durability of the cable tray system .