How to connect copper strips in cable trays

Copper strips can be bonded to cable trays using conductive clamps or adhesive copper fabric strips to ensure electrical continuity and proper grounding.

Grounding and Bonding Practices

When connecting copper strips to a cable tray, the primary goal is to maintain electrical continuity and grounding. Metallic cable trays can serve as the Equipment Grounding Conductor (EGC), but proper bonding is essential to ensure safety under fault conditions . Each section of the tray should be electrically connected using grounding clamps or conductive connectors, which mechanically secure the copper strip to the tray and prevent it from being displaced by magnetic forces during a fault . For aluminum trays, bare copper should not be used due to the risk of electrolytic corrosion. Instead, use insulated copper conductors and remove insulation only at bonding points with tin- or zinc-plated connectors .

Using Conductive Copper Strips

Conductive copper fabric strips are a practical solution for connecting copper to cable trays, especially for shielded terminations or EMI/RFI protection . These strips are flexible, durable, and feature dual-sided conductive adhesive, allowing current to flow through both sides. To use them:

1. Prepare the surface: Clean the tray section or cable jacket where the strip will be applied.
2. Wrap or place the strip: Position the copper strip over the area to be bonded.
3. Secure the connection: Press the adhesive firmly to ensure good electrical contact.
4. Integrate with grounding system: Connect the strip to the main grounding bus or EGC as required. These strips are particularly useful for shielded cables, where the drain wire can be wrapped around the cable jacket and tacked down with the copper strip to maintain continuity .

Installation Considerations

• Ensure the cross-sectional area of the tray or copper strip meets the minimum requirements for the circuit's protective device rating .
• Use appropriate connectors or clamps compatible with the tray material (steel, aluminum, or coated trays) to avoid corrosion and maintain conductivity .
• Maintain mechanical stability: Copper strips should be anchored to prevent movement under vibration or fault currents.
• Follow NEC or local electrical codes for grounding and bonding of cable trays, including spacing and connection requirements . By following these practices, copper strips can be effectively integrated with cable trays to provide reliable grounding, bonding, and EMI/RFI protection.