Load Capacity and Safety Factor: Ensure the bracket's rated load exceeds your cable weight with a standard safety factor of 1. Material and Corrosion Protection: Specify hot-dip galvanized steel, powder-coated steel, or stainless steel (e., 304 or 316 grade) for harsh. Electrical cable tray wall penetration firestopping Scope: Firestopping for busway, cable trays, cables, and trunking passing through walls in enclosed electrical installations. Fittings can, on the one hand, be used for horizontal or vertical changing of the routing direction or, on the other, to change the height or width of the. The following charts give the number of 3M pillows needed to completely firestop an opening that cable tray passes through. * Two (2) sticks of moldable putty (part number FSP-MPS) are also needed for each opening. Materials like steel, aluminum, and fiber-reinforced plastics all behave differently in the presence of fire, so understanding. When selecting the best cable tray bracket for your project, prioritize strength, compatibility with tray type, and environmental resistance. For example, if you're installing a ladder-style cable tray in an industrial facility, galvanized steel single-arm brackets often provide the ideal balance. The mostly combustible cable sheaths and insulation allow a fire to spread along the cable at rapid speed.