Technical guide to firestopping cable tray and slab penetrations in electrical shafts; specifies materials, packing limits, waterstop heights and installation sequence. Vertical-tray flame tests are commonly used in the wire and cable industry to analyze cable flame propagation for industrial control and power cables. The purpose of this test is to determine whether the flame. Fires involving electrical cables are one of the main fire hazards in Nuclear Power Plants (NPPs). Where cables pass through shafts, walls, slabs, or enter electrical panels or cabinets, openings shall be tightly sealed with firestopping materials in accordance with. The large scale experiments consisted of loaded cable trays situated in vertical and horizontal configurations. For the horizontal experiments, from one.