Cable tray round steel grounding specifications table

Round steel cable trays are metallic conduits designed for mechanical support and grounding, with dimensions and grounding practices standardized for safety and electrical continuity.Material and ConstructionRound steel cable trays are typically made from galvanized steel, stainless steel (AISI 316L), or pre-galvanized steel to provide mechanical strength and corrosion resistance . The steel may be finished with hot-dip galvanization or tin/zinc plating to prevent corrosion, especially in moist environments . Ladder-type or tubular steel trays are common, with 16-gauge steel tubing often used for rails and stringers .DimensionsWhile exact dimensions vary by manufacturer, typical round steel cable trays follow these general ranges:Tray TypeWidth (in)Height (in)Rail ThicknessLoad ClassLight Duty Ladder4–122–416–14 gaNEMA 12A/12BMedium Duty Ladder12–244–614–12 gaSeries 2–3Heavy Duty Ladder24–366–812–10 gaSeries 4–5Round Tubular2–82–616–12 gaVaries by spanRung spacing is typically 6–9 inches (150–230 mm) to support cables and maintain bend radius . Width is measured outside-to-outside, and load class defines the maximum supported cable weight over a given span .Grounding and BondingRound steel cable trays can serve as the Equipment Grounding Conductor (EGC) if installed by qualified personnel . Key grounding practices include:Bonding each tray section with grounding clamps to ensure electrical continuity.Using insulated conductors when connecting to aluminum trays to prevent electrolytic corrosion.Connecting multi-conductor cables with individual EGCs to the tray or bonding points.Following NEC Article 250.96 for grounding metallic cable trays, regardless of whether the tray itself is used as the EGC . Grounding clamps also provide mechanical anchoring to prevent displacement of the EGC under fault current conditions .Installation NotesTrays can be mounted on floors, walls, ceilings, or equipment racks .Ensure minimum bend radius for cables exiting the tray.Use solid or ventilated covers depending on heat dissipation and electromagnetic interference requirements .Verify manufacturer-specific load ratings and compliance with NFPA 70 Article 392 for metallic cable trays . These specifications ensure that round steel cable trays provide both mechanical support and safe electrical grounding for cable management in industrial, commercial, and data center applications.