Abstract: An improved grounded-tank compressed-gas circuit-interrupter of the two-break rotatable contact-arm type is provided having an improved grounded metallic-tank configuration to accommodate interiorly therein one or more arc-extinguishing assemblages of the two-break rotating contact-arm variety.In some embodiments of the invention, only a single rotatable contact-arm assemblage is provided, the axis of rotation being generally horizontal, and a vertically-extending generally cylindrical grounded metallic dead-tank housing being provided to accommodate interiorly therein the arc-extinguishing assemblage, with the line-terminal connections for the rotatable contact-arm assemblage extending generally laterally, horizontally to a pair of upstanding terminal-bushings, the latter being generally vertically disposed, and extending downwardly into off-jutting metallic tank portions interconnected with the main cylindrical tank housing.