Sectionalized porcelain insulator having removable circuit breaker

In a porcelain insulator type circuit breaker including a lower porcelain tube secured to a supporting frame, an upper porcelain tube mounted on said lower porcelain tube in axial alignment therewith, and an interrupting unit provided in said upper porcelain tube, the improvement which comprises means for interconnecting said upper porcelain tube and said lower porcelain tube in a manner permitting rotation of said upper porcelain tube relative to said lower porcelain tube to displace said upper porcelain tube from axial alignment with said lower porcelain tube, said means comprising a jack bolt for upwardly forcing said upper porcelain tube from said lower porcelain tube and a hinge for interconnecting said upper and lower porcelain tubes so that said jacked-up upper porcelain tube can be rotated about said hinge so as to permit removal of said interrupting unit from the lower end of the rotated upper tube.