Polymer (non-metallic) cable trays generally do not need to be grounded because they are non-conductive, unlike metallic trays which must be grounded for safety.

Key Points

Non-conductive material: Polymer cable trays, such as those made from fiberglass-reinforced plastic (FRP) or PVC, are electrically insulating. This means they do not carry fault currents and therefore do not serve as an equipment grounding conductor (EGC). Grounding is primarily required for metallic trays to prevent shock hazards and ensure electrical continuity under fault conditions . Metallic tray grounding: In contrast, all metallic cable trays must be grounded according to NEC Article 250.96. Metallic trays can act as an EGC if they meet cross-sectional area requirements, and bonding jumpers may be needed to maintain electrical continuity across tray sections . Improper grounding of metallic trays can lead to shock hazards, equipment damage, and failed inspections . Safety considerations for polymer trays: While polymer trays do not require grounding, it is still important to ensure that any metallic components attached to the tray (such as supports, fasteners, or cable clamps) are properly bonded if they could become energized. Additionally, polymer trays should be installed according to manufacturer specifications to maintain mechanical integrity and fire safety. Summary:

• Polymer cable trays: No grounding required due to non-conductive nature.
• Metallic cable trays: Grounding and bonding mandatory; may serve as EGC if sized correctly.
• Best practice: Ensure any metallic accessories or nearby conductive parts are properly grounded to maintain overall system safety. By understanding the distinction between metallic and polymer trays, you can ensure compliance with electrical codes while maintaining safety in cable management systems.