Insulators are categorized by installation method into suspension insulators and pole insulators; by the type of insulating material used, into porcelain, glass, and composite (also known as synthetic) insulators; by voltage class, into low-voltage and high-voltage insulators; by environmental conditions, into anti-pollution insulators for polluted areas; by voltage type, into DC insulators; and there are also various specialized insulators, such as insulating crossarms, semiconductor glaze insulators, tension insulators for distribution, spool insulators, and wiring insulators, etc. Additionally, based on the possibility of insulation breakdown, they can be divided into two types: Type A, non-breakdown insulators, and Type B, breakdown-prone insulators.