Provides technical requirements concerning the construction, testing, and performance of metal cable tray systems. Addresses shipping. us-trations without notice. The mechanical and electrical characteristics, tests, certifications, overall quality management, recommendations mentioned. This standard is based on corresponding IEC publication 61084-1:1991 'Forcable trunking and ducting system for electrical installations: Part 1General requirements' issued by the International Electrotechnical Commission. The information has been organized for. 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. A rung spacing of 6 to 9 inches (150 to 230 mm) is preferable when.