Explore various cable tray types and sizes for electrical installations. Solid-Bottom. 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. Learn about ladder, perforated, solid-bottom, wire mesh, and channel trays in this complete guide. The mechanical and electrical characteristics, tests, certifications, overall quality management, recommendations mentioned. Cable tray and cable ladder systems are an ideal alternative to electrical conduit systems. Why use cable tray? A properly designed and installed cable tray system provides outstanding reliability for a facility's control, communication, data, instrumentation and power systems cabling and wiring.