Assessing the fire risk of electrical cables using a cone calorimeter

摘要

The presented study deals with the fire risk of electrical cables. Samples of three-core electrical power cables and two-core electrical control cables were investigated. The influence of the mutual spacing between the cables and the thermal conductivity of the material under the cables (underlying material) on fire risk was assessed in the study. The fire risk was determined using a cone calorimeter (at a heat flux of 50 kWm(-2)) and an oxygen bomb calorimeter. The fire risk was assessed based on parameters quantifying the released heat, toxicity and amount of combustion products and flashover category. The heat release rate, total heat release and the effective heat of combustion increase with increased spacing between the cables and decreased thermal conductivity of the underlying material. The carbon monoxide yield increases with the increase in the thermal conductivity of the underlying material. The influence of the spacing between cables on the carbon monoxide yield (in the interval 0-1800 s) depends on the thermal conductivity of the underlying material. At low thermal conductivity, the carbon monoxide yield decreases as the spacing decreases, with the opposite trend (with some exceptions) at high thermal conductivity. Smoke yield decreases with increasing thermal conductivity of the underlying material and also increases with increased spacing between cables. Neither the thermal conductivity of the underlying material nor the spacing between cables has an influence on the flashover category of the cables investigated.