How to drill holes in a tray-type cable tray

Holes in cable trays are typically drilled using a drill or hydraulic punching machine, with templates or splice plates to ensure accurate placement.

Tools and Equipment

To drill holes in cable trays, you will need:

• Drilling machine or hydraulic punching machine for structural steel or aluminum trays .
• Drill bits appropriate for the tray material (steel, aluminum, or fiber-reinforced plastic), .
• Templates or splice plates to mark hole positions accurately .
• Debris cleaning tools to remove metal shavings after drilling .

Hole Placement and Method

1. Marking the Position: Use a splice plate or a drill jig as a template to locate the hole positions. This ensures that holes for splice plates or dropouts are aligned correctly .
2. Field Drilling: For field-cut trays, drill holes after cutting to length. Ensure that splice plates are placed on the outside of the tray, with bolt heads on the inside unless otherwise specified .
3. Support Considerations: Avoid placing splice plate holes directly over support joints. Position them between supports or at quarter points to maintain structural integrity .
4. Hole Sizes: Common hole sizes include 7/16” for solid bottom trays and 5/16” for dropouts, but always follow manufacturer specifications .

Best Practices

• Use proper safety equipment such as gloves and eye protection when drilling .
• Ensure accurate measurements to prevent misalignment of splice plates or connectors .
• Consider thermal expansion: Allow for expansion and contraction in long tray runs by spacing splice plates appropriately .
• Clean debris after drilling to prevent damage to cables or hardware .

Summary

Drilling holes in cable trays is a precise process that requires the right tools, templates, and careful placement. Using splice plates as guides, following manufacturer specifications, and maintaining proper support spacing ensures a safe, structurally sound, and efficient cable tray installation .