Do cable trays need to be grounded Price

All metallic cable trays must be grounded to ensure safety, while non-metallic trays do not require grounding; costs vary depending on materials and installation methods.

Grounding Requirements

Metallic cable trays are required to be grounded according to NEC Article 250.96 and Article 392.60. Grounding ensures that any stray electrical currents are safely diverted to the earth, preventing shocks, equipment damage, or fire hazards . The tray itself can serve as an equipment grounding conductor (EGC) if it meets cross-sectional area requirements, but in some cases, a separate grounding conductor is recommended for added safety . Non-metallic trays (e.g., fiberglass or plastic) do not conduct electricity and therefore do not require grounding . Proper grounding involves securely connecting the tray sections using grounding clamps, bolts, or welds, and ensuring that materials like copper or galvanized steel are compatible with the tray to prevent corrosion, especially when combining dissimilar metals like copper and aluminum .

Grounding Methods

1. Full-Length Grounding Conductor: A continuous wire runs along the tray, providing a reliable path for fault currents .
2. Tray as EGC: The metallic tray itself can act as the grounding conductor if it meets NEC conductivity and strength requirements .
3. Bonding at Joints: Grounding clamps or bimetallic washers are used at tray connections to maintain electrical continuity and prevent galvanic corrosion .

Cost Considerations

The cost of grounding a cable tray system depends on several factors:

• Material of the tray: Aluminum trays are lighter but may require bimetallic washers when paired with copper grounding; steel trays are heavier but more durable .
• Grounding wire type: Copper wire offers excellent conductivity but is more expensive than galvanized steel or stainless steel .
• Installation complexity: Continuous grounding conductors, bonding clamps, and proper torque on bolts increase labor costs.
• Tray length and number of joints: Longer runs and more connections increase material and labor costs. As a rough estimate, grounding materials and installation can range from $2 to $10 per foot depending on tray size, material, and labor rates, with additional costs for specialized connectors or corrosion-resistant components .

Summary

• Metallic trays must be grounded for safety and NEC compliance.
• Non-metallic trays do not require grounding.
• Grounding can be achieved via the tray itself or a separate conductor, with proper bonding at joints.
• Costs vary based on tray material, grounding wire type, and installation complexity, typically ranging from a few dollars per foot to higher for specialized setups. Proper grounding not only ensures compliance but also prevents electrical hazards and prolongs the life of the cable tray system.