Experimental study of flame spread over PE‐insulated single copper core wire under varying pressure and electric current

Abstract

Summary In this study, the flame spread over a thin wire with overload current (0‐16 A) has been experimentally investigated at both normal pressure (Hefei: altitude 50 m, 100 kPa) and reduced pressure (Lijiang: altitude 2400 m, 76 kPa; Lhasa: altitude 3650 m, 64 kPa). Polyethylene‐insulated single‐core wires, comprising Cu as the inner core of diameter 0.30, 0.50, and 0.80 mm and insulation thickness 0.15 and 0.30 mm, are used as samples. The experimental results clearly indicate that the height of the flame increases with the electric current and ambient pressure, but the flame width changes only slightly. At identical conditions, the finer the wire, the faster the flame spreads. The flame spread rate increases with the electric current and ambient pressure. A simplified thermal balance analysis concerning the load current is developed to calculate the flame spread rate, and the calculated flame spread rates are shown to be fairly consistent with the experimental values at different electric currents for different wires at both ambient pressures. In addition, the coupled effect of electric current and ambient pressure on the flame spread is discussed. These results may be meaningful for promoting the research process of wire fire safety.

Experimental Study on the Thermoplastic Dripping and Flame Spread Behaviors of Energized Electrical Wire under Reduced Atmospheric Pressure

“…The influencing factors of the relevant fire spreading considered in these studies including inclination angles [ 5 ], AC electrical fields [ 6 ], oxygen concentration [ 7 ], external radiation intensity [ 8 ], ambient pressure [ 9 , 10 , 11 ], and gravity [ 12 , 13 , 14 , 15 ]. Besides these influencing factors, their ignition behaviors were investigated under various scenarios, such as short-term overcurrent [ 16 , 17 ], external heat flux [ 18 ], arc formation [ 19 , 20 ], subatmospheric [ 21 , 22 ], and microgravity [ 23 , 24 ]. A few studies have also been carried out on investigating the thermoplastic properties of those melt drips [ 25 , 26 , 27 , 28 ].…”