• The design, development, and application of an accelerated water treeing test (AWTT) system are presented. • A current measurement system is designed to use on the medium voltage side. • The AWTT system can detect the life of medium voltage cables between 15 and 36kV. • The AWTT system is designed according to HD 620 S2 European cable standard. • The AWTT system tested two different medium voltage cables successfully. In this study, the design and implementation of a new cable test system were carried out for the aging process of medium voltage (MV) cables. Two different pools, medium voltage systems, and microcontroller-based control circuits of these systems were developed for the accelerated water tree test (AWTT) process. Moreover, a new current measurement system was proposed for improve insulation to MV applications. A water aging process was applied to 15 and 36 kV distribution system cables to test the performance of the developed test system. Since the aging test process of the 15 kV cable has been completed, the breakdown voltage of the cable was determined. However, the aging test process for the 36 kV cable continues. The test results show that the AWTT process for two medium voltage cables was carried out successfully by the developed microcontroller-based test system by satisfying the requirement of international standards.