Gas-insulated electrical switchgear for medium and high voltage electrical distribution networks comprising: - a first enclosure insulated in a gas and provided with at least one electrical connection means (2, 3) and at least one mechanical connection means; - an operating means integrated inside a second enclosure, arranged between at least one bar of a main circuit and at least one branch bar, said operating means comprising a gas breaking switch, said second enclosure equipped with the operating means being comprised inside the first enclosure; - an actuating element configured to actuate the operating means that performs the functions of breaking, making, disconnecting, and grounding; and - an operating mechanism to cause actuation of the actuating element; - wherein the mechanical connection means couples the operating mechanism to the first enclosure; the gas-insulated electrical switchgear being characterized in that: - the switchgear further comprises a plurality of covers that incorporate inside, concentrically, the bars of the main circuit and the branch bars, the medium between the bars (6, 7) and the cover being a gas; - the first enclosure comprises inside the covers that incorporate the bars of the main circuit and branch bars; - the covers are made of an electrically non-conductive material and comprise hollow parts, having cylindrical geometry, which are coupled to each other by means of at least one first joining means; and in that - the bars of the main circuit and the branch bars have a cylindrical geometry, and in that they further comprise at least one second joining means that allows joining between bars of the main circuit or joining between branch bars. - a first enclosure insulated in a gas and provided with at least one electrical connection means (2, 3) and at least one mechanical connection means; - an operating means integrated inside a second enclosure, arranged between at least one bar of a main circuit and at least one branch bar, said operating means comprising a gas breaking switch, said second enclosure equipped with the operating means being comprised inside the first enclosure; - an actuating element configured to actuate the operating means that performs the functions of breaking, making, disconnecting, and grounding; and - an operating mechanism to cause actuation of the actuating element; - wherein the mechanical connection means couples the operating mechanism to the first enclosure; - the switchgear further comprises a plurality of covers that incorporate inside, concentrically, the bars of the main circuit and the branch bars, the medium between the bars (6, 7) and the cover being a gas; - the first enclosure comprises inside the covers that incorporate the bars of the main circuit and branch bars; - the covers are made of an electrically non-conductive material and comprise hollow parts, having cylindrical geometry, which are coupled to each other by means of at least one first joining means; and in that - the bars of the main circuit and the branch bars have a cylindrical geometry, and in that they further comprise at least one second joining means that allows joining between bars of the main circuit or joining between branch bars.