Reconnecting a cable tray ground wire requires ensuring a continuous, low-impedance path to ground using proper bonding methods, materials, and NEC-compliant practices.

Key Steps for Reconnection

1. Verify the Cable Tray Type and Material

• Determine if the tray is steel, aluminum, or wire mesh, as this affects the choice of grounding conductor and connectors.
• Avoid bare copper in aluminum trays to prevent electrolytic corrosion; use insulated conductors with exposed ends for bonding points ( ). 2. Ensure Compliance with NEC Standards
• All metallic cable trays must be grounded per NEC Article 250.96, regardless of whether the tray itself serves as the Equipment Grounding Conductor (EGC) ( ).
• If the tray is used as the EGC, confirm that the metal cross-sectional area meets NEC Table 392.60(A) requirements for the protective device rating ( ). 3. Bonding the Ground Wire
• Use grounding clamps, bolts, or welds to securely attach the ground wire to each tray section or at alternate sections. This ensures mechanical stability and electrical continuity under fault conditions ( ).
• For insulated conductors, remove insulation at the bonding point and use tin- or zinc-plated connectors to prevent corrosion ( ). 4. Continuous Grounding Path
• Run a full-length grounding conductor along the tray if the tray cannot serve as the EGC or if additional safety is desired ( ).
• Ensure all joints and splice plates maintain electrical continuity; bonding jumpers may be used if the tray sections are not electrically continuous ( ). 5. Material Selection
• Use copper wire for excellent conductivity, hot-dip galvanized steel for durability, or stainless steel in harsh environments ( ).
• Maintain a grounding resistance of 4 ohms or less to ensure effective fault current diversion ( ). 6. Safety Precautions
• Keep grounding wires clear of flammable materials and moisture.
• Only qualified personnel should perform reconnection to ensure compliance and safety ( ).

Summary

Reconnecting a cable tray ground wire involves identifying the tray material, ensuring NEC compliance, securely bonding the ground wire, and maintaining a continuous low-resistance path. Proper material selection and mechanical attachment are critical to prevent corrosion, maintain electrical continuity, and ensure the safety of the electrical system ( ).