Yes, low-voltage cable trays must be grounded to ensure safety, prevent electrical hazards, and maintain system reliability.

Why Grounding is Necessary

Low-voltage cable trays require grounding to provide a safe path for fault currents, protecting both personnel and equipment from accidental electrical discharge . Proper grounding also minimizes electrical noise, reduces the risk of surges, and ensures system stability over time . Even if the tray is not used as an equipment grounding conductor (EGC), grounding is still required under NEC Article 250.96 for all metallic trays .

Grounding and Bonding Practices

• Metallic Trays: All metallic cable trays must be electrically continuous and bonded at all splice points. Mechanical connections alone may not provide reliable continuity, so bonding jumpers are often used to maintain an effective grounding path .
• Separate EGC: A separate equipment grounding conductor can be installed inside or attached to the tray, sized according to NEC tables and the tray's length and current load .
• Tray as EGC: In some installations, the tray itself can serve as the EGC if it meets cross-sectional area requirements and is properly bonded .
• Material Considerations: Bare copper conductors should not be used in aluminum trays to avoid electrolytic corrosion; insulated conductors with proper bonding connections are recommended .

Special Considerations for Low-Voltage Systems

Low-voltage systems typically carry smaller currents than high-voltage systems, so grounding wire sizing and bonding techniques are tailored accordingly . Grounding also helps protect sensitive signal and communication circuits from electromagnetic interference (EMI) and lightning-induced voltages . For non-metallic trays, grounding may not be required for power circuits but is recommended for shielding and EMI protection .

Summary

Grounding low-voltage cable trays is mandatory for safety and code compliance. Proper installation involves ensuring electrical continuity, using bonding jumpers where necessary, and selecting appropriate conductor sizes and materials. This practice protects personnel, prevents equipment damage, and maintains reliable operation of both power and communication systems .