They consist of steel ladder type cable trays and a support system. The struits are restrained to the building structure by anchor or dowel. The fire protection of the nuclear island in nuclear power plants is classified as an important non-safety grade system, and its function is to extinguish fires quickly, limit the spread of fire, and minimize the impact of fire on equipment that performs safety functions. The nuclear island area. A major objective of the actual cable fire experimental series is the investigation of the effects of a naturally ventilated fire on vertically routed cables (worst case) with differ- ent cable insulation materials (PVC (polyvinyl chloride) and FRNC (fire retardant non- corrosive)).