This paper describes the lightning overvoltage occurred differently according to installation methods of arresters and overhead grounding wire in case of double circuits distribution systems. First, the analysis models are established considering the severe case between upper and lower distribution line, when the direct lightning surge strikes to the overhead grounding wire. The lightning overvoltage is variously analyzed with the change of grounding interval and resistance, arrester installation interval as well as the magnitude of surge using EMTP. After simulation results are compared with the BIL which is now used at field, the authors propose the methods for suitable shielding in domestic distribution systems.