In addition to the conductive function of ordinary bus ducts, fire-resistant bus ducts must also maintain circuit integrity for a certain period of time under flame conditions. In addition to meeting the national standard GB7251.6, our company's fire-resistant bus duct products also meet the GA/T537-200S standard. The conductor surface is wrapped with more than 3 layers of mica tape insulation (heat resistant to 1100°C), and silicon wool (heat resistant to 21100°C) is used for insulation between the conductor and the casing. The casing is made of high-quality steel plates, and the surface of the casing is electrostatically sprayed with refractory powder after rust removal, oil removal, sulfonation and drying, so that the casing will not burn under flame conditions. The casing structure is an internal and external groove shape, which prevents the flame from directly or indirectly burning the conductor and destroying the insulation, and ensures the necessary protection level and circuit integrity under the spraying state.