Abstract: In an electrical distribution apparatus a switchgear device has a fixed element disposed within a shielded region of an enclosure of the apparatus, and a movable element supported for movement between a closed position in contact with the fixed element and an open position out of contact with the fixed element. The movable element is disposed at least partially within an access region of the enclosure when in the open position. A panel is supported between the shielded and access regions, and includes a slot through which the movable element passes during movement between the closed and open positions. A barrier member is movable horizontally relative to the panel between a blocking position covering the slot and a non-blocking position exposing the slot. The barrier member prevents inadvertent contact with the fixed element through the slot and prevents movement of the movable element between the open and closed positions when in the blocking position.

Abstract: An electrical switchgear apparatus for use in selectively connecting a primary power line with a tap power line includes a housing in which a switch assembly is disposed. The housing includes a source side wall and a tap side wall generally opposed to the source side wall, and conductors extend through each of the source and tap side walls. A live front terminator is electrically connected with the source side conductor and is adapted to be connected with the primary power line, while a dead front terminator electrically connects with the second insulated conductor and is adapted to be connected with the tap power line. A dead front enclosure surrounds the insulated conductors, the live front terminator, and the dead front terminator. Observation windows in the source side wall and in the dead front enclosure permit visual inspection of the switch assembly from outside of enclosure.

Abstract: A current interrupting apparatus adapted to be interposed in either a single or multiple phase electrical circuit includes a fuse interposed in each phase of the circuit. A current interrupter is electrically connected in series with each fuse for interrupting the current through the circuit, each current interrupter including a pair of normally closed electrical contacts and structure for opening the pair of contacts in response to a fault current of a magnitude different from the magnitude of current necessary to cause fusing of the fusible element of the fuse. A current interrupter triggering circuit is included in the apparatus for triggering operation of the contact opening structure of all of the current interrupters in response to fusing of the fusible element of any of the fuses to protect the circuit from the effects of single phasing.

Abstract: A motor operator for local or remote shifting of switchgear contacts toward either open or closed positions includes a reversible motor and rotatable drive screw mounted on common support structure for simultaneous pivoting movement as a drive nut translates fore-and-aft along the length of the screw. The drive nut includes an outer body and an inner sleeve which is set into free-wheeling motion whenever the sleeve comes into contact with either of two stops mounted on the screw defining respective end limits of travel for the nut. A drive element normally coupling the nut to an operating shaft of the switchgear is removable to allow the shaft to be manually rotated with a wrench when desired, and removal of the drive element reduces the likelihood that the worker is injured upon unintentional activation of the motor while the operating shaft is turned by hand.

Abstract: An electronic sectionalizer mechanism includes upper and lower contact mounting structure, and a sectionalizer tube carrying a logic circuit is telescopically received within the lower contact mounting structure. Once fault current conditions downstream of the sectionalizer mechanism are detected by the logic circuit, an actuator is fired and the tube drops in a longitudinal, non-lateral motion toward an isolated or open circuit position. In preferred embodiments of the invention, a pin of the actuator shifts along an axis parallel to the longitudinal axis of the tube so that immediate drop-out of the tube is assured. The sectionalizer mechanism requires comparatively little space for operating clearances and this is especially adapted for use on a retrofit basis within the confines of an existing subsurface or pad-mounted switchgear cabinet; additionally, the sectionalizer mechanism may also be installed in existing overhead mounting structure for cutouts.

Abstract: An improved, lowcost double-fused vacuum switchgear apparatus designed for underground electrical distribution systems is provided which makes use of a specially configured oil tank-defining wall and insulative protective fuse well sleeves to give enhanced protection to workmen performing unauthorized energized servicing of the unit, while also using a minimum of dielectric oil and separate wall components. The preferred tank includes an oblique sidewall eliminating unnecessary oil space in the tank, while each fuse well is equipped with an insulative sleeve which guides fuse removal and installation and largely prevents short-circuiting even during energized servicing. The fuse assembly preferably includes a current-limiting fuse and a series-coupled expulsion fuse, the latter being oriented in the wells for directing conductive arcing gases downwardly and away from the switchgear components.

Abstract: A combination dropout assembly adapted for use with protective cutouts in an electrical distribution system comprises a current limiting fuse electrically connected in series with an explusion-type fuse, and mechanically coupled in skewed relation to the latter, whereby the assembly provides reliable full range fault current protection yet is sufficiently compact in length to matingly span the gate between conductive terminals of conventional 15 KV class opengate cutouts found in many existing electrical distributioon systems. Overload and low to medium fault current protection is provided by the expulsion fuse, while high range fault currents are cleared by operation of the current limiting fuse.