Grounding is possible inside the cable tray

Cable trays can serve as grounding conductors, but proper grounding wires or bonding are often required to ensure safety and compliance.

Cable Tray as a Grounding Conductor

Metallic cable trays can be used as the Equipment Grounding Conductor (EGC) in certain installations, allowing the tray itself to carry fault currents safely to ground . This is typically applicable when the tray meets specific conductivity, cross-sectional area, and mechanical strength requirements. For example, steel or aluminum trays must meet minimum metal area standards to safely function as an EGC . Non-metallic trays, however, cannot serve as grounding conductors and require separate grounding wires .

Grounding Wires and Bonding

Even when the tray is used as an EGC, it is often recommended to run a continuous grounding wire along the tray or bond the tray sections together using grounding clamps or jumpers . This ensures electrical continuity across tray sections, prevents voltage differences, and provides a reliable path for fault currents. Grounding wires should be insulated in aluminum trays to prevent electrolytic corrosion . Bonding also connects the tray to equipment enclosures, conduit, or the main power source, enhancing safety and compliance with standards like NEC, IEC, or IS .

Safety and Compliance

Proper grounding of cable trays:

• Prevents electric shock by safely directing fault currents to earth .
• Reduces electrical noise and interference, important for sensitive electronics .
• Ensures compliance with electrical codes and standards .
• Facilitates maintenance and troubleshooting by providing a clear path for fault detection .

Summary

While metallic cable trays can sometimes act as the grounding path, best practice is to ensure all tray sections are bonded and, where necessary, to run a dedicated grounding conductor. Non-metallic trays always require separate grounding. Proper installation, bonding, and compliance with standards are essential to maintain safety, prevent equipment damage, and reduce the risk of electrical hazards .