Pre-drill pilot holes in the marked spots, being careful not to drill too deep or wide. Double-check that the tray is level and firmly attached. Mark the cable tray route based on your electrical cable tray design and site. Installing a cable tray system requires careful planning to ensure it can support the weight of the cables and adheres to electrical safety codes. Before starting, ensure you have. What tools do I use to drill clean holes in both the plastic and aluminum enclosures so that the cable glands fit snugly without any gaps? I tried searching for M20 drill bits and thread taping, but couldnt really find anything solid. Edit: Link to datasheet of cable gland:. Welcome to Engineerings. in this document have been tested extens ompetent professional en completely installed, without damage either to conductors or structural system use maintain spacing or to keep cables in place when the tray is ect the minimum bend ra-dius for cables as they exit the bottom of the cable tray. Covers are available for 45° and 90° bends, angle-adjustable bends, T pieces, add-on tees and cross-overs.