The heating mode of a cable line under one-phase arcing ground fault is considered in this paper along with an assessment of the scale of cable insulation caused by a temperature increase in the fault location. Based on the enclosed arcing discharge model, we have constructed a system of equations describing the heating mode of a cable line during the evolution of one-phase arcing ground fault over time. We have obtained the time history of the temperature field of the considered cable line using finite-element analysis. Based on the obtained data, we were able to draw several conclusions about the influence of such parameters as the operating voltage on the behavior of the heating mode, along with typical time and dimension scales of these processes. We have formulated a number of suggestions focused on decreasing the probability of the development of considerable thermal destruction of a cable line under one-phase arcing ground fault that could potentially cause two-phase fault