Should cables routed in cable trays be flame-retardant

Surfaces should be coated with fire-retardant paint to slow flame spread and increase heat resistance. Install fire barriers within the tray to isolate different fire zones. When cable trays pass through walls or floors, seal openings using fire-rated penetration sealing materials. Tray Type and Material Selection Indoor: Painted steel or galvanized trays. Outdoor: Hot-dip galvanized or. Must be listed as having adequate fire resistance and low-smoke producing characteristics by exhibiting a flame travel distance that does not exceed 1. 5 m (5 ft) and by generating a maximum peak optical density of 0. Power, low voltage control. Electrical lines can ignite themselves due to overheating or a short-circuit or they can be set alight by the external influence of fire or heat. [pdf]