In this paper, an experimental study is carried out in order to compute the impacts of shading effect on photovoltaic (PV) system performance. Four numbers of 20W solar PV modules are considered and arrange in the 2x2 size of array for extensive analysis. Moreover, a performance comparison is carried out for all the four PV modules organized in seriesparallel (SP), Total cross-tied (TCT) and Latin Square puzzle based Latin Square-Total cross-tied (LS-TCT) electrical connections. In addition of this, three types of shadow test cases are taken to show the impact on behaviour of currentvoltage (I-V) and power-voltage (P-V) curves. Furthermore, the output power from PV array reduces as well as P-V curves exhibit multiple power maxima points such as local and global maximum power point (GMPP) due to shadow effect. The performance index parameters such as power at GMPP, minimum power losses, fill factor (FF) and efficiency are analysed experimentally under the distinguish shadow cases.