Fire Resistant Wires and Cables

Product Introduction

Fire resistant cables are special wires capable of maintaining power supply for specified duration under fire conditions, classified into Grade A and Grade B fire resistance. Rated voltages are commonly 300/500V and 0.6/1kV, complying with GB/T 19666 and GB/T 12706 national standards. Typical models include NH-YJV, NH-VV, NH-KVV fire resistant control cables and flexible mineral insulated fire resistant cables. Upgraded from ordinary power cables with additional fireproof thermal barriers, they prevent rapid insulation breakdown in fires and sustain power for fire water pumps, smoke exhaust fans, emergency lighting, fire elevators and other vital fire fighting equipment. They are widely deployed in fire power circuits of high-rise buildings, hospitals, subways, underground utility tunnels and shopping malls with dense crowds.

Internal Structure

Conventional extruded fire resistant cables adopt multi-layer protective structure from inside out. The innermost compact stranded oxygen-free copper conductor ensures stable conductivity and even temperature rise under load. Multiple layers of mica tape are wrapped around conductors as the core fireproof layer; dense inorganic heat insulation barrier forms under open flame to block heat and delay insulation breakdown. XLPE or PVC insulation is extruded outside mica tape to guarantee normal electrical insulation under daily conditions. Flame retardant filler fills gaps between multi-cores to keep cable round and restrain flame spread. Inner liner and steel tape armor are optionally equipped to enhance compression and impact resistance against falling debris in fires. The outermost flame retardant PVC or LSZH sheath curbs flame propagation. High-grade flexible mineral fire resistant cables adopt inorganic mica mineral insulation and corrugated copper sheath without combustible organic materials, delivering far longer fire endurance and superior waterproof & moisture-proof performance.

Core Performance Advantages

Fire resistance is clearly graded. Grade B cables can sustain continuous power supply over 90 minutes under 750~950℃ flame combustion; Grade A cables withstand higher temperature and longer burning duration to meet strict fire codes for super high-rise buildings. Electrical performance matches ordinary power cables under normal operation with stable insulation and low voltage drop for reliable daily power supply. The flame retardant sheath slows flame spreading along cables and limits fire scope. LSZH variants generate thin smoke without toxic corrosive hydrogen halide gas during combustion, improving visibility for evacuation and fire rescue in enclosed spaces, and avoid corrosion to building steel structures and precise fire control equipment. Armored cables feature high mechanical strength against extrusion, impact and rodent damage for safe laying in trenches and ceilings. Certain types deliver moisture and slight oil resistance for long-term service in damp basements.

Application Scenarios

Main fire power distribution cables for high-rise apartments, super high-rise office buildings and large commercial complexes; emergency power circuits in crowded public buildings such as hospitals, exhibition centers, stadiums and schools; fire wiring for enclosed underground spaces including subways, tunnels, utility tunnels and civil air defense projects; dedicated power lines for fire water pumps, smoke exhaust fans, fire elevators, emergency lighting and fire alarm systems; backup fire power cables for chemical plants and warehouses; power wiring for fire renovation projects of old buildings.