Insulators are categorized by installation methods, including suspension insulators and post insulators; by the insulation material used, they can be porcelain, glass, or composite (also known as synthetic) insulators; by voltage grade, they are classified into low-voltage and high-voltage insulators; by environmental conditions, there are dirt-resistant insulators for polluted areas; by voltage type, there are DC insulators. Additionally, there are special-purpose insulators such as insulating crossarms, semiconductor glazed insulators, tension insulators for distribution, reel insulators, and wiring insulators. Furthermore, based on the possibility of insulation breakdown, they are divided into two types: A-type insulators, which are non-breakdown, and B-type insulators, which are breakdown-prone.