Explore various cable tray types and sizes for electrical installations. Solid-Bottom. 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. A rung spacing of 6 to 9 inches (150 to 230 mm) is preferable when the cable tray cont d for instrumentation and control applications that require. us-trations without notice. All illustrations, descriptions and technical information included in this document are provided as indications and can cable trays are equivalent. The mechanical and electrical characteristics, tests, certifications, overall quality management, recommendations mentioned. Cable trays play a vital role in supporting electrical cables and wires in commercial, industrial, and utility installations. Below are 100 questions that comprehensively cover the basic definitions, material classifications, selection.