How to ground a wire mesh cable tray

For wire mesh cable trays, installing a separate grounding wire is recommended to ensure safety and compliance, as the tray itself is not always suitable as an equipment grounding conductor.Use of Mesh Cable Trays as Grounding ConductorsWire mesh cable trays are often fabricated in the field by cutting and modifying straight sections, which can reduce their current-carrying capability and electrical continuity. Because of this, using the tray itself as an equipment grounding conductor (EGC) is generally not recommended. If the tray is intended to serve as an EGC, a separate grounding wire should be installed to provide a reliable low-impedance path to ground and to reduce noise or stray currents, especially when supporting cables with built-in EGCs or sensitive signal/control cables .Installation of a Grounding WireWhen installing a grounding wire for a mesh cable tray:Continuous Conductor: Run a continuous grounding wire along the length of the tray to ensure a steady path for fault currents .Connection Points: Secure the grounding wire at each tray section using grounding clamps, bolts, or mechanical connectors. Insulated conductors are preferred for aluminum trays to prevent electrolytic corrosion, with insulation removed at bonding points .Material Selection: Use materials with good conductivity and corrosion resistance, such as copper, stainless steel, or hot-dip galvanized steel .Bonding to Building Steel: The tray and grounding wire should be bonded to building steel or a non-system ground to maintain electrical continuity and safety .Compliance and SafetyNEC Requirements: All metallic cable trays must be grounded according to NEC Article 250.96, regardless of whether the tray is used as an EGC .Low Impedance Path: Ensure the grounding system provides a low-impedance path to facilitate the operation of overcurrent protection devices and to minimize voltage rise during fault conditions .Periodic Bonding: For long runs, bonding jumpers may be required every 50–65 feet to maintain continuity and UL classification .SummaryWhile metallic cable trays can sometimes serve as an EGC, wire mesh trays are better served with a dedicated grounding wire due to their structural modifications and reduced current-carrying capacity. Proper installation involves continuous conductors, secure bonding at each section, corrosion-resistant materials, and adherence to NEC grounding standards to ensure safety and reliable operation .