The low voltage (LV) distribution cable networks were installed some decades ago but the new paradigm in electric power engineering generates new requirements from these old assets. The distributed generation, storage and new appliances can cause high variation of load and reverse power flow, nevertheless the LV cable grid was not designed to these new stresses. The aggregate load and generation can surpass the rated capacity of the cable lines causing short term temperature increasing. This temperature stress can decrease the expected lifetime of the cable lines. In this study the short term thermal overload of LV distribution cables was investigated. The experiments were executed on PVC insulated LV cable samples and electrical and mechanical properties of the cable jacket were investigated. The effect of these short-term overloads on the expected lifetime of cables is introduced and non-destructive measurement for tracking the effect of the short term thermal overloads on the cable is suggested.