Fire sealing of cable penetrations is required by building regulations. Where cables pass through shafts, walls, slabs, or enter electrical panels or cabinets, openings shall be tightly sealed with firestopping materials in accordance with design requirements. Process flow: reserved openings → busway installation → distribution box positioning and installation →. This document outlines the key requirements for cable tray layout, installation, and fireproofing in industrial and commercial environments. Cables are made of copper which will also accelerate the heat transfer through the. The bottom line is that electricians and other trades must prevent fire and smoke from traveling throughout a building via the holes they've drilled in walls, ceilings, and floors for conduit, cable trays, piping, etc.