Research on combustion characteristics and fire risk of ZR-BVR wires with different thermal aging degrees

The high temperature may cause the insulation of electrical cables to age, resulting in insulation breakdown and electrical fire. The influence of two key factors, namely incident external heat flux and thermal aging time, and aged wires were prepared. A cone calorimeter is used to test the combustion performance of different aging degrees ZR-BVR wires under 35KW m-2 and 50KW m-2 radiation. In addition, the time-to-ignition (TTI), heat release rate (HRR), gas generation rate, and smoke generation rate under the two kinds of external radiation were compared and analyzed. And, the fire risk of the samples was comprehensively evaluated by Analytic hierarchy process (AHP) and entropy mass method. The results indicated that the longer the aging time, the less likely the sample to be ignited, the longer the time to reach the peak heat release rate increases, and the peak heat release rate (pHRR) of ZR-BVR10 is the largest, with a maximum value of 208.64KW m-2, the consumption of O2 and the production of CO2 and CO decreased significantly, and there was a great difference before and after 30 days of aging.