Is welding allowed to form cable trays

Yes, welding is allowed and commonly used to form metal cable trays, provided it follows proper standards and safety procedures.

Welding in Cable Tray Systems

Welding is a standard method for joining metal components in cable tray systems, particularly for steel wire mesh trays and other metallic trays used in industrial and commercial installations . Welded joints enhance the structural stability of the tray, ensuring it can safely support electrical cables and resist mechanical stresses . Factory or field welding may be performed depending on the installation requirements, but all welds must meet strength and quality standards, often verified through destructive testing or inspection .

Material Considerations

Cable trays are typically made from carbon steel, stainless steel, or aluminum alloys. Each material has specific welding requirements:

• Carbon steel trays: Welded using standard steel welding techniques; surfaces may be treated post-welding for corrosion protection .
• Stainless steel trays: Require careful welding to maintain corrosion resistance and avoid stress corrosion cracking .
• Aluminum trays: Welding is possible but requires specialized techniques due to aluminum's high thermal conductivity and oxide layer .

Compliance and Safety

When welding cable trays, it is essential to comply with NEC Article 392 and manufacturer guidelines . Key points include:

• Ensuring welded trays maintain structural integrity and proper load capacity.
• Using trays in permitted locations (not in hoistways or inaccessible areas).
• Maintaining grounding continuity if metallic trays are used as equipment grounding conductors.
• Following factory or field welding procedures to prevent weak joints or damage to protective coatings .

Advantages and Considerations

Advantages of welding cable trays:

• Stronger joints and enhanced durability.
• Reduced risk of mechanical failure in large-scale installations.
• Flexibility in creating custom tray layouts and supports. Considerations:
• Requires skilled personnel and proper equipment.
• May involve additional surface treatment after welding to prevent corrosion.
• Field welding may be more time-consuming than using pre-fabricated bolted trays . In summary, welding is an accepted and effective method for forming metal cable trays, provided it is performed according to manufacturer specifications, NEC requirements, and proper safety practices .