Insulators are categorized by installation method into suspended insulators and pillar insulators; by the type of insulating material used, they are divided into porcelain insulators, glass insulators, and composite insulators (also known as synthetic insulators); by voltage class, they are categorized as 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 various special-purpose insulators, such as insulating crossarms, semiconductor glaze insulators, tension insulators for distribution, spool insulators, and wiring insulators. Furthermore, based on the possibility of insulation breakdown, they can be classified into two types: A-type, non-breakdown insulators, and B-type, breakdown-insulators.