The global market size of composite insulators is gradually increasing in contrast to that of ceramic insulators. In 2010, composite insulators took on 39% of the global market size, while ceramic insulators took on 50.5%. In 2015, the market size of composite insulators reached 41%, increasing by 2%, while the market size of ceramic insulators fell to 48.2%. The utilization of silicone materials as an insulator in high-voltage electrical industry has been increasing from day to day. These insulators are subjected to severe weather conditions during their operating life. Electrolyte liquids have different conductivities owing to the amount of ionized substances that they contain. Ionized substances are the factors that facilitate electron movement; at the end, electron avalanches occur, which cause deterioration. In this work, two different electrolyte liquids that had different characteristics in terms of conductivity were used with a view of analyzing the breakdown behavior of silicone insulators. Silicone insulators were examined on an inclined-plane test setup in compliance with IEC 587 and ASTM D 2303-97 standards. Different conductive electrolyte liquids were used to investigate the breakdown behavior of silicone insulators. Furthermore, harmonic analysis was performed in accordance with current-time signals collected from the ground electrode. Silicone insulators that were used in the experiment deteriorated at different times.