Effect of deposition of combustible matter onto electric power cables

The thermal insulating and self-heating effect of combustible dust deposited on electric power cables is discussed. In many practical situations, such as factories and warehouses, cable runs are exposed to the deposition of many insulating and combustible dusts over long periods. Critical thicknesses for these layers are calculated, i.e. the thicknesses for which cable failure will occur, either due to the onset of runaway combustion reaction in the dust layer, or even before the onset of runaway reaction when temperatures can reach the melting point of PVC insulation.