NEMA FG 1 – This standard specifies the manufacturing requirements for nonmetallic (fiberglass) cable trays (such as; ladder cable tray trough or ventilated cable tray, solid bottom or nonventillated cable tray and channel cable tray) and associated fittings for use in accordance. NEMA FG 1 – This standard specifies the manufacturing requirements for nonmetallic (fiberglass) cable trays (such as; ladder cable tray trough or ventilated cable tray, solid bottom or nonventillated cable tray and channel cable tray) and associated fittings for use in accordance. This standard specifies the requirements for nonmetallic cable trays and associated fittings designed for use in accordance with the rules of the Canadian Electrical Code (CEC) Part 1, and the National Electrical Code® (NEC). Covers construction and test requirements for. Fire resistance testing evaluates how well cable trays can withstand fire and prevent flames from spreading. This includes checking their flammability, smoke production, toxic gas emissions, and ability to block heat and fire. Why Does. ucts; however, as an alternative DIN 4102-12 can be used. The primary rulebook used in the safe use of cable trays is NEC Article 392.