Location of feed hole and outdoor cable tray

Feed holes in cable trays are typically located along the bottom or sides of the tray, with outdoor trays requiring weep holes to prevent water accumulation.

Feed Hole Placement

Feed holes are used to allow cables to exit the tray at specific points or to attach accessories. For solid-bottom cable trays, feed holes should be drilled in the bottom, sides, or ends of the tray depending on cable routing needs. When installing dropouts for cable exits, field-drilled holes are often used as templates to ensure proper alignment with the tray width and cable size.

Pre-punched holes on some tray systems, like Eaton's B-Line series, allow easy attachment of accessories without additional drilling.

Outdoor Cable Tray Considerations

Outdoor cable trays must account for moisture and environmental exposure. Solid-bottom trays installed outdoors should include 1/4-inch weep holes drilled into the tray bottom at the sides and in the middle every 3 feet to prevent water accumulation. Ventilated trays naturally allow water to drain through the rungs or mesh openings, reducing the need for additional holes.

Tray Support and Mounting

Cable trays should be mounted on structural supports such as wall brackets, ceiling hangers, or strut systems. Maintain a minimum of 12 inches of clearance above and to the side of the tray for installation and maintenance access. Supports must be strong enough to handle the tray load, and trays should remain accessible and not installed in hoistways or areas prone to physical damage.

Horizontal and vertical bends, T-pieces, and crossovers can be used to change routing direction while maintaining proper support.

Material and Environmental Considerations

Outdoor trays are typically made from aluminum, galvanized steel, or stainless steel to resist corrosion. The choice of material depends on environmental conditions, such as exposure to moisture, UV, or corrosive agents. Stainless steel or coated steel is preferred in highly corrosive environments.

Summary

Feed holes: Bottom, sides, or ends; pre-punched or field-drilled for cable exits and accessories. Outdoor trays: Include weep holes for solid-bottom trays; ventilated trays allow natural drainage. Support: Use brackets, hangers, or struts; maintain clearance for access.

Material: Choose corrosion-resistant materials suitable for outdoor conditions. Proper placement of feed holes and careful installation of outdoor cable trays ensures reliable cable management, prevents water damage, and maintains compliance with safety standards.