What are the copper wires next to cable trays called

Copper wires can be used to bond and ground cable trays, but proper methods and precautions are essential to ensure safety and prevent corrosion.

Grounding and Bonding Practices

Cable trays, especially metallic ones, can serve as an Equipment Grounding Conductor (EGC), but they must be properly bonded to ensure electrical continuity and safety . When using copper wires:

• Bonding to Cable Tray Sections: If a separate EGC is installed in or on the cable tray, it should be bonded to each or alternate tray sections using grounding clamps. This ensures both electrical continuity and mechanical stability under fault conditions .
• Avoid Bare Copper in Aluminum Trays: Placing a bare copper wire in an aluminum tray can cause electrolytic corrosion, particularly in moist environments. To prevent this, use insulated copper conductors and remove insulation only at bonding points, using tin or zinc-plated connectors .
• Mechanical Connections: Cable trays are connected using splice plates, bolted connections, clamps, or quick-connect systems. These connections provide structural stability and ensure that the copper bonding wires maintain a secure electrical path .

Safety and Code Considerations

• All metallic cable trays must be grounded according to Article 250.96 of the National Electrical Code, regardless of whether they are used as an EGC .
• The cross-sectional area of the tray metal must meet minimum requirements if the tray itself is used as the EGC, depending on the circuit breaker rating .
• Steel trays should not be used as EGCs for circuits with ground-fault protection above 600 A, and aluminum trays above 2000 A .

Practical Tips

• Use insulated copper wires for bonding in aluminum trays to prevent corrosion.
• Ensure tight mechanical connections between tray sections to maintain both structural integrity and electrical continuity.
• Regularly inspect connections for looseness or corrosion, especially in environments with high humidity or chemical exposure. By following these practices, copper wires can safely and effectively be used to bond and ground cable trays, ensuring both electrical safety and long-term durability .