Connect the cable tray to the grounding electrode

To safely connect a metallic cable tray to a grounding electrode, ensure continuous electrical bonding across all tray sections and secure a properly sized grounding conductor to the building grounding electrode system.Step 1: Ensure Electrical Continuity of the Cable TrayAll metallic cable tray sections must be electrically continuous. This requires bonding at every splice point using bonding jumpers or conductive connectors to eliminate gaps in conductivity. Mechanical connections alone may not guarantee continuity, so verify that each tray section and fitting maintains a low-resistance path for fault current (NEC Article 392) .Step 2: Use an Equipment Grounding Conductor (EGC)If the cable tray is not used as the EGC, install a separate insulated EGC along the tray. Bond the EGC to each or alternate tray sections using grounding clamps. Avoid bare copper in aluminum trays to prevent electrolytic corrosion; instead, use insulated conductors with insulation removed only at bonding points, and use tin- or zinc-plated connectors .Step 3: Connect to the Grounding Electrode System (GES)The cable tray or EGC must be securely connected to the building's grounding electrode system. This system may include metal underground water pipes, ground rods, or concrete-encased electrodes. Use listed pressure connectors, exothermic welding, or other approved methods suitable for the conductor and electrode material. Ensure the connection is permanent, low-impedance, and capable of safely conducting fault current .Step 4: Verify Compliance and SafetyConfirm that the tray and EGC sizing meet NEC requirements for the circuit's protective device rating.Ensure all metallic components, supports, and fittings are bonded to maintain a continuous path.Avoid using the tray as the sole EGC for circuits with high ground-fault protection ratings (e.g., steel trays above 600 A, aluminum above 2000 A) .Test continuity and resistance to verify a reliable grounding path. By following these steps, the cable tray system will provide a safe, low-resistance path for fault currents, protect personnel and equipment, and comply with NEC grounding and bonding standards.