The ZN85-40.5 PT handcart indoor vacuum circuit breaker is an intelligent switchgear designed specifically for 40.5kV power systems, integrating voltage transformer (PT) function to achieve voltage monitoring and protection integration. Adopting vacuum arc extinguishing technology, the short-circuit current breaking capacity is as high as 40kA, and the modular design of the handcart supports quick insertion and removal, increasing maintenance efficiency by 50%. Compliant with GB/T 1984 and IEC 62271-100 standards, with a mechanical lifespan of over 10000 cycles and a protection level of IP4X, suitable for high humidity and dusty industrial and mining power distribution environments. Suitable for medium voltage cabinets in substations, high-voltage circuits in data centers, and key power nodes in the steel/chemical industry, providing an environmentally friendly solution with "zero SF6 emissions".