Indoor high voltage load switch FKN12-12d/T630-20 and indoor high voltage load switch fuse brake composite apparatus FKN12-12DR/T125-31.5 can be used into distribution system of industry, mining, enterprise, residence district, high building and school, park etc. As indoor ac three phases 12kv, 50hz net ring electric supply and final terminal distribution equipment, that can break/make rated load current, make rated short circuit current, and break transformer idle current, certain distance of overhead line, cable line and capacitor bank and capacitor current. Load switch fuse brake combination electric cabinet can break rated short circuit current in one time. That can be the protection of distribution unit, distribution and control of electric energy in the electric system. This switch installed ground connection knife and spring operation mechanism (operated by electric and/or manual) with the function of making capacity, and has the ability of far movement and control.