Abstract: A plug-in terminal block is driven into a companion receptacle and drawn out of the receptacle by an actuator pivoted to the receptacle. The actuator, having driven the plug-in block into the receptacle, is in its blocking position, blocking the plug-in block against removal from the receptacle and blocking insertion of a terminal block into the receptacle. A locking device locks the actuator in its blocking position. The actuator is accessible for operating the locking device and for tilting the actuator via the door opening of an enclosure.

Abstract: The described fuse holders or analogous electrical equipment is blocked by a padlock and a clip against being casually changed from its locked condition so that the controlled circuit remains energized or denergized. The clip is captive between the fuse carrier of the fuse holder and the fuse holder's receptacle but the clip is no longer captive when the fuse carrier is removed from the receptacle.

Abstract: The disclosed electrical apparatus involves multiple poles of an electrical device which bear links for plug-in connection to a set of three-phase bus bars; the links for the three spaced-apart bus bars are shaped and proportioned alike.

Abstract: The disclosed non-interchangeable plug-in electrical connector includes a first connection device bearing a series of break-away interference elements, to be broken away selectively; plug-in interference members are plugged into the second connection device, bearing interference elements which, in the preferred embodiment, are break-away elements to be removed selectively so as to become complementary to the retained interference elements of the first device; the plug-in interference members have break-away extensions that facilitate insertion of the interference members, the extensions then being broken away and serving in removal of selected break-away interference elements.

Abstract: The described fuse holders include a receptacle unit and a fuse-carrier unit having means, especially a lever, for driving the units apart and forcing the release of the contacts of each unit from the other. Multiple single-fuse fuse holders can be ganged for operation coordinately. A wire shroud fixed to the receptacle serves also as a releasable latch to hold the receptacle on a mounting rail. The receptacle is adaptable either to have wire connections or rear stud terminals.

Abstract: An assembly of one, two or more rows of terminal blocks are movable to allow limited extension and contraction of each row so that the spacing of terminals of a row of the terminal blocks can be varied. A selected form of elongated member has spaced-apart formations that cooperate with the respective terminal blocks to fix the terminals of the row of terminal blocks at inch-based modular positions or at millimeter-based modular positions corresponding to the spacing of electrical equipment terminals.

Abstract: The disclosed switching fusible apparatus includes a fuse-holding device receivable in a receptacle and rotatable to "ON", "OFF" and "RELEASE" positions. The fuse-holding device comprises a fuse holder for containing a larger fuse and it may comprise the fuse holder containing an adapter which, in turn, contains a smaller fuse. A slot in the exposed end of the fuse holder receives a screw-driver for selectively turning the fuse-holding device when tool-operable apparatus is required, or a knob is interlocked with the slot in high-profile apparatus. Contact is made to each end cap of each fuse in the "ON" position of the fuse-holding device by a contact tab that is not significantly yielding per se but which is rendered prominently resilient by oppositely extending resilient torsion supports extending along the elongated fuse-holding device.

Abstract: A push nut and a male member are disclosed having cooperating buttress threads. The push nut is divided into sectors, each of which has multiple segments that comprise the nut's thread. The adjacent edges of the successive sectors are connected to each other by a resilient corrugation arranged to distribute the stress equally between the ends of each thread segment and equally among the thread segments of each sector.

Abstract: The disclosed electrical connection apparatus includes an enclosure of electrical insulation having a cavity containing a screw-activated clamp for gripping a wire against a contact member, the screw being accessible for operation at the wire-entry side of the enclosure.

Abstract: The disclosed rejection fuse holder for accepting grooved-terminal cartridge fuses and rejecting ungrooved-terminal cartridge fuses utilizes rejection elements having fuse-engaging edges of special sharpness that dig into and block insertion of ungrooved fuse terminals. In a particularly economical fuse-clip terminal construction, each of a pair of fuse-gripping arms bears a length of wire as the rejection element, carried by its respective arm, with a sharp-edged end facing the direction of fuse insertion, assembled to the fuse-clip arm without resort to a fastening operation.

Abstract: The disclosed embodiments represent novel compact terminal blocks and novel compact side-by-side assemblies of an elongated terminal block, a wiring channel at one side, and an electric circuit structure at its opposite side. Current paths slant prominently in traversing the terminal block, including slanted end portions of wiring from the wiring channel and slanted conductors in the terminal block. Corner recesses in a first side of the terminal block admit the slanted end portions of wiring from the wiring channel. Corner recesses in the second side of the terminal block opposite the first side contain projecting terminals for plug-in connection to companion plug-in terminals of an electric circuit structure or for soldered connection to conductors of the electric circuit structure, or the second-side recesses (in another embodiment) admit slanted end portions of wiring from a second wiring channel to the terminal block's connecting devices.