The underground power cable failures introduce challenges to the reliability of underground residential distribution networks. Smart Grid initiatives have interest to improve equipment reliability. Asset management of several utilities are interested towards online cable insulation condition monitoring and health index evaluation. This dissertation demonstrates a new technique for online condition assessment of power cable insulation condition based on capacitor switching transient voltage measurements. While majority of utilities in USA are following corrective maintenance for MV cables, only few utilities have procedures in place for offline preventive maintenance of MV cables. The technique demonstrated in this research will enable all utilities to carry out preventive online monitoring of MV power cables. This dissertation also demonstrates that capacitive test point of cable elbow connector can be used to measure switching transients for power cables in service. This technique can be easily incorporated into existing capacitive test points of cable accessories. This technique has a potential to develop and deploy measurement units for online monitoring of power cables.