In this work, the benefits of a modern personal computer are used to get a deeper insight into the processes occurring in a ceramic material just before and during a dielectric breakdown. Especially, a model to simulate the thermal breakdown behavior in a two-phase material is presented, which is based on a random resistor network. To study the influence of different parameters on the thermal breakdown, simulations were done changing the values of a set of six variables, e.g. external voltage, resistivity, etc. The resulting plots time vs. maximum temperature are shown.