Insulating sheet materials, also known as dielectrics, are substances that do not conduct electricity or conduct it minimally under the application of direct voltage. The primary function of insulating sheet materials is to isolate conductors at different potential levels within electrical equipment, allowing current to flow along a specific path. They also serve as mechanical supports and fasteners, as well as for arc extinction, heat dissipation, energy storage, moisture and mold prevention, and to improve the potential distribution of the electric field and protect conductors.