Bare cable tray connection

Bare cable tray connections require proper mechanical fastening and grounding to ensure electrical continuity and safety, following NEC guidelines and material compatibility.Mechanical ConnectionCable trays are connected using specialized brackets, splice plates, or fasteners designed for the tray type and material. Each section of the tray should be aligned and bolted securely to maintain structural integrity and support the weight of the cables. Fasteners must be tightened according to manufacturer specifications to prevent movement or misalignment under load. For aluminum trays, avoid direct contact with bare copper conductors to prevent electrolytic corrosion; insulated conductors or tin/zinc-plated connectors are recommended for bonding points .Electrical Bonding and GroundingBare cable trays can serve as the Equipment Grounding Conductor (EGC) if they meet the minimum cross-sectional area requirements specified in NEC Article 392.60(A). Each tray section should be bonded to adjacent sections using grounding clamps, which provide both electrical continuity and mechanical anchoring. This ensures that under fault conditions, magnetic forces do not dislodge the conductor. For aluminum trays, a bare copper EGC is not recommended in moist environments; instead, use an insulated conductor with exposed ends at bonding points .Material ConsiderationsSteel trays: Can be used as EGC for circuits with ground-fault protection up to 600 A.Aluminum trays: Should not be used as EGC for circuits above 2000 A ground-fault protection.Stainless steel trays: Provide high corrosion resistance and can be bonded similarly to steel trays .Best PracticesVerify that the tray system meets the minimum cross-sectional area for grounding based on the maximum fuse or breaker rating.Use manufacturer-approved connectors and brackets to maintain system integrity.Ensure all bonding points are clean, free of paint or oxidation, and properly torqued.Avoid using trays as walkways or supports for personnel, as this can compromise both safety and electrical continuity . By following these mechanical and electrical connection practices, bare cable tray systems can safely support cables while providing reliable grounding and bonding in compliance with NEC standards.