Abstract: Apparatus is disclosed for preventing a person from coming into dangerously close proximity with an earth-embedded temporary electrical grounding rod so as to lessen the likelihood of electrical shock in the event of a fault current. The overall protective device of the invention includes an earth-embedded, temporary, electrical grounding rod, a mounting collar threadably secured to the upper end of the grounding rod, and a plurality of insulative, elongated struts removably secured to the collar and extending outwardly and obliquely therefrom. A perimeter-defining rope element extends about the grounding rod in a laterally spaced, elevated position relative thereto, and is supported by the oblique struts.

Abstract: A torque-limiting adapter for an elongated, insulative hot line clamp stick is provided which allows completely safe, accurate take-up of workpieces only to desired torque levels. The adapter preferably includes an elongated, tubular, axially rotatable head removably mounted onto the work end of a conventional clamp stick and housing a torque-limiting device; the input of the device is connected to the existing rotatable clamp stick, while the torque output of the device is connected to a manipulative tool, such as a pivotal hook. The tool is coupled to the head such that they rotate in unison until the desired torque level is reached, and is further coupled for axial shifting into and out of the head for safety purposes.

Abstract: An improved electrical conductor cover is provided which essentially completely surrounds an energized conductor and is resistant to inadvertent, impact-induced dislocation of the cover during use. The cover includes an elongated, tubular, conductor-receiving section and a pair of ribbed, normally biased-together legs extending from the section. The legs normally are in abutting engagement, but can be separated for positioning the cover on a conductor; the ribs are spaced along the length of the legs and serve to cooperatively maintain the conductor within the tubular section even in the event of an accidental impact normally tending to spread the legs and thus expose the covered conductor. The cover also includes a molded-in-place, threaded head which projects only through the outer surface of the cover for allowing connection of a manipulative handle to the cover without the need for rivets or the like which extend completely through the insulative wall of the cover.

Abstract: A tool for safe, manual shifting and manipulation of energized lines is provided which finds special utility in mines or other close areas where conditions of moisture and the like make it mandatory that electrical equipment be handled with great care. The tool includes an elongated, insulative rod having, adjacent one end thereof, a pair of spaced, opposed, fixed, hook-like, spiral, cable-engaging fingers. In use, the fingers are placed astride an electric cable or the like and the rod is rotated axially so that the fingers pass under and cooperatively engage and capture the cable therebetween, thus permitting easy shifting and movement of the cable. Particular features of the tool include the complete elimination of any mechanical moving parts, and the special configuration of the cable-engaging fingers permitting easy lateral shifting of a cable without fear that the cable will become disengaged and fall free of the tool.

Abstract: A high voltage oil expulsion fuse having multiple fuse wire bores which vent into opposed chambers which communicate with the oil medium for convective flow of oil through the bores during normal operation is provided wherein a pressure sensitive valve associated with one of the chambers allows only unidirectional venting of deionizing gases from the fuse when a fault or overload occurs causing sequential melting of the fusible elements in respective bores. Oil derived gases generated by the last to melt fusible element vent in both directions from the corresponding bore and the pressure thereof causes the valve to close forcing such gases to flow through the remaining bores to assure complete evacuation of conductive material from all bores upon fuse operation. In this manner, interruption against a high rate of rise of recovery voltage is assured and delayed failure of the fuse under normal frequency recovery voltage is also prevented.

Abstract: An arc track resistant, high voltage, filled synthetic resin insulator is disclosed which exhibits a wide range of desirable qualities heretofore unobtainable with any single type of prior insulator. The insulator hereof unexpectedly gives excellent arc track and flame resistance, along with a flexibilized yet rugged construction having good weatherability properties. These qualities are achieved through use of a relatively critical selection of components and proportions which also facilitate cast construction of the insulators by giving a pourable, yet highly filled liquid casting composition during the fabrication stage. The insulators include critical quantities of hydrated alumina (from about 60 to 75% by weight) and a synthetic resin matrix having expoxidized castor oil (18 to 24% by weight) and a glycidyl rigidizer therein, along with a curing agent and accelerator.

Abstract: A current limiting fuse is provided with a number of discrete current limiting elements coupled electrically in parallel between a pair of conductive terminals, and a fused gap assembly in series with each current limiting element whereby full range fault current protection is provided by the fuse. Under the influence of high range fault currents, the current limiting elements operate collectively to quickly clear the fault, while low fault currents are interrupted by fusing of the fused gaps to present a plurality of parallel arc gaps in the elements, which parallel gaps function in turn to sequentially distribute the full fault to each element resulting in successive interruption by the elements and ultimate clearing of the low range fault. In a second form of the invention shiftable contact sets in each element are operably coupled with a low fault current responsive device to create the arc gaps required for sequential operation of the current limiting elements.

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.

Abstract: A high dielectric strength seal between the encapsulant and the outwardly projecting actuating arm of an externally operable encapsulated vacuum switch includes a fluid-receiving sealed cavity surrounding the actuating arm between the latter and the encapsulant. An externally accessible valve permits charging of the cavity with a dielectric fluid subsequent to encapsulation of the switch to insure displacement of air from the interface between the encapsulant and actuating arm, thereby greatly reducing the likelihood of corona formation and dielectric breakdown of the seal. Additionally, the dielectric fluid may be pressurized through the valve to preclude infusion of conductive contaminants into the cavity. In preferred forms, an accumulator is in fluid communication with the cavity to permit thermal expansion and contraction of the dielectric fluid without undesired leakage or cavitation of the liquid.

Abstract: A lightweight, grounding clamp assembly utilizes a grounding stud for rigid mounting on an electrical device and incorporates nondeformable, stud-engaging bight which renders the assembly capable of safely conducting extremely high fault currents in the order of 100,000 amps or more. The bight forms a part of an open-ended passage extending through the clamp body which passage is completely encircled by the body to resist distortion of the bight under the influence of high fault currents. In preferred embodiments, the passage has a keyhole-shaped cross-section and the stud is configured to be complementally received and retained within the neck of the keyhole.

Abstract: A C-type electrical grounding clamp is provided for high voltage distribution lines wherein structure on the main body of the clamp presents at least a pair of separate, cooperable ground cable receiving elements oriented with the longitudinal axes of the cable passages in perpendicular relationship relative to one another. The user may thereby employ a plurality of the clamps all of identical construction for either phase-over-phase or phase-by-phase grounding in a manner wherein in each instance the grounding cables between adjacent conductors are all essentially parallel and of minimum length to span the distance therebetween for maximum resistance to fault current induced grounding cable whipping, and minimum imposition of non-fault stresses thereon. The clamps are especially adapted for supporting dual grounding cables between each pair of proximal conductors.

Abstract: A relatively low cost dual element fuse link including a meltable solder junction has a pair of thermally insulated, serpentine, fusible elements supported on opposite sides of the junction for increasing the heat transferred to the junction by the elements in response to a given current carried by the link such that the junction will be caused to melt at lower current values thereby providing the link with an increased speed ratio. A pair of cylindrical porcelain insulators disposed along respective serpentine elements present the desired thermal insulation as well as provide structural stability to the elements precluding deformation of their serpentine shape when the fuse link is under tension as in a distribution system cutout. The serpentine shape of the elements presents an increased element length which in turn reduces the temperature gradient along the elements thereby reducing axial conductive heat loss from the ends of the elements remote from the solder junction.

Abstract: A high current grounding assembly especially adapted for electrically interconnecting and grounding substation phase busses conductors is provided which includes rigid metallic connector elements capable of handling extremely high fault current loads without violent whipping or other motions. The clamp and connector assembly, or one of the phase busses, is connected to ground in order to protect linemen or other workers in the vicinity of the assembly from the effects of fault or inductive currents. In preferred forms, novel conductor-gripping clamps and rigid tubular connector elements may be partially or completely preassembled and thereafter installed on phase busses.

Abstract: Pad-mounted double-fused switchgear especially adapted for use in underground distribution systems is provided which includes an oil tank having manually operable vacuum switch apparatus therein in conjunction with closely adjacent, series-connected, combination current limiting fuse-expulsion link protective fuse structure for maintaining the required momentary electrical rating of the overall switch apparatus notwithstanding of a relatively low-rated switch element, and for providing thermal protection for the switchgear. Double-fusing within the oil tank also serves to reduce electrical duty on upstream and downstream equipment, increases the interruption rating of the switchgear, and enhances overall system coordination.

Abstract: An improved, spring-biased take-up clamp assembly for elongated tie-down elements such as cables, ropes or mobile home tie-down straps is provided which permits simplified, infinitely adjustable take-up and tightening of the tie-down element with secure locking at any desired position and without the use of conventional turnbuckles or other devices using interference-fit structure for spindle-retaining purposes. In preferred forms the assembly includes a rotatable take-up mandrel or spindle for a tie-down element, an apertured mounting plate fixed to the upper end of an embedded earth anchor, and a motion-checking snubber spring operatively coupled between the strap spindle and mounting plate for holding the strap against loosening under tension loads while at the same time permitting relatively easy, one-man tightening thereof as desired.

Abstract: A lightweight, easily installable, anchored foundation for electrical equipment or the like is provided which includes a foam-filled, force-transmitting frusto-conical housing tensionably connected to a plurality of adjacent, buried earth anchors having remote load-bearing helices thereon in order to create a prestressed bulb of relatively compacted soil between the housing base and anchor helices which greatly enhances the holding power of the foundation under both tension and compression loads. In preferred forms the foundation exhibits approximately the same support strength as poured concrete, but can be more quickly installed and employed at remote locations or on loose soil which would normally preclude the use of concrete.

Abstract: An easily installable, high load capacity deadending apparatus for securing the end of lines such as guy cables and the like to anchoring structure is provided which includes a tapered wedge block in conjunction with a helically preformed line tie adapted to grip the line and preferably extend around and engage the remote end of the wedge block for securing the latter against substantial axial movement; a socket casting having a complementally tapered bore is applied over the wedge block and line tie thereround to complete the apparatus and permit connection thereof to an earth anchor or like device so that the socket and block are biased together in mutual gripping interengagement. In practice, as the line experiences increasing tension loads, the wedge block and socket are pulled into tight interengagement which in turn causes a tighter grip of the line and increases the overall holding power of the deadending apparatus.