Abstract: A rotary selector switch comprises a generally flat blade mounted for rotation in its own plane about an axis passing through it into and out of contact with one or more of several spaced terminal contacts.

Abstract: A pothead installation for a high voltage, high pressure oil-filled, electric cable in which the pothead is surrounded by a metal tank at ground potential, the tank being filled with sulfur hexafluoride gas under pressure. Oil and nitrogen within the pothead are conveyed to the exterior of the tank by a tube of insulating material having electrical characteristics and a length adequate to withstand at least the voltage difference between the cable conductor and the tank and having physical characteristics adequate to withstand at least the pressures of the oil and nitrogen. At the end of the tube at the tank wall, the tube is connected to a reservoir which is mounted exteriorly of the tank and which accumulates the oil and nitrogen. The reservoir has a venting valve for venting the nitrogen and oil, has a sight gauge for monitoring the oil level in the reservoir, and may have a float switch connected thereto for operating an alarm when the volume of the nitrogen exceeds a predetermined value.

Abstract: A grounding and test switch for a fully enclosed pressurized gas insulated high voltage system wherein the conductors are completely isolated in an SF.sub.6 or other gas insulating environment. The grounding switch is provided with a contact arm and a movable contact within the enclosure to engage a stationary contact connected to or on the conductor or device inside the enclosure. The contact arm is operable through a gas tight seal from outside the enclosure. The contact arm slides with respect to another stationary contact which provides a direct and positive electrical connection thereto so that the contact arm, when engaged with the first mentioned stationary contact forms a conducting bridge to ground between the first mentioned and second mentioned stationary contact.

Abstract: Inner conductors of isolated phase bus sections arranged end to end are joined by a multiplicity of longitudinally extending, annularly arrayed contact fingers which are biased radially inwardly against the conductors being joined with one end of each finger riding in a groove provided therefor on the exterior of one conductor and the other end of the finger being biased against the end of the next adjacent conductor to make slidable contact engagement therewith; a single dielectric shield surrounds both ends of the conductors and the contact fingers and is non-rigidly fastened at its longitudinal ends to the respective shells around each of the endwise adjacent conductors; springs extend between the shield and the fingers to bias the fingers against the conductors; the shield and finger arrangements permit the maximum width for the inner conductors enabling maximum quantities of contact fingers to be used and this arrangement also permits great misalignment between conductors, or tilting of one conductor wit