Abstract: A miniature circuit breaker, which includes a circuit breaker housing, a button mechanism, and an indicating apparatus. The circuit breaker housing includes an indicating hole arranged in one side thereof, the button mechanism is in sliding fit with the circuit breaker housing, the indicating apparatus is in driving fit with the button mechanism, and when the button mechanism is pressed to switch on the miniature circuit breaker, the button mechanism drives the indicating apparatus to shield the indicating hole. The indicating apparatus thereof may indicate a switching-on state of the circuit breaker when the circuit breaker is switched on, thus improving a safety of electricity consumption.

Abstract: A switching apparatus includes one or more electric pole units, each electric pole unit comprising a fixed contact, a movable contact, a first pole terminal, a second pole terminal, and a motion transmission arrangement to reversibly move the movable contact. The motion transmission arrangement includes a conductive motion transmission member coupled to the movable contact. The first pole terminal is in electrical connection to the fixed contact while the second pole terminal includes a first coupling region in electrical connection with a second coupling region of the conductive motion transmission member. Each electric pole unit further includes a shielding element formed by a conductive hollow body and arranged in a relative fixed position with respect to the second pole terminal and the motion transmission member. The shielding element is arranged to at least partially surround the first coupling and the second coupling region.

Abstract: A network service and transformer safety protector on a secondary side of a network transformer tank system. The network service and transformer safety protector is positioned between the network transformer and a secondary network distribution system and is configured to connect and disconnect a transformer from the secondary network. The network service and transformer safety protector is attached to the outside of the transformer tank.

Abstract: A current sensing modular system, which allows sensing the phase current and/or the around-fault or zero-sequence current, having to that end at least a first module having at least one phase current sensor embedded therein and a second module having a zero-sequence current sensor embedded therein. The first module is independent of the second module, both modules being installed directly in the connection elements, i.e., in the connection point between at least one bushing and at least one connector of at least one grid cable.

Abstract: A gas-insulated switching device including, inside a pressure tank: a vacuum valve having a movable contact provided on one side of a movable conductor, and a fixed contact provided to a fixed conductor; an insulation rod connected to another side of the movable conductor led out through a bellows from the vacuum valve; and an airtight container in which the insulation rod and the other side of the movable conductor are stored, wherein an internal space of the bellows and an internal space of the airtight container communicate with each other, one side of the vacuum valve is fixed to a tank wall via an insulation support body, another side of the vacuum valve is connected to the tank wall via the airtight container, and the airtight container insulates the vacuum valve and the tank wall from each other, and is slidable in a movable direction of the movable conductor.

Abstract: The invention relates to the use of a gas as a medium for electrically isolating and/or extinguishing electric arcs, said gas comprising a hexafluorobutene. The invention also relates to an electric device comprising a sealed chamber inside which electric components and said gas are located.

Abstract: A bidirectional driving mechanism 10 has a drive-side linkage rod 11, a driven-side linkage rod 13, two levers 12 that link the drive-side linkage rod with the driven-side linkage rod, and a guide 14 that regulates the operation of the drive-side linkage rod 11 and the driven-side linkage rod 13. A moveable pin 18 is passed through a first groove cam 16 of the drive-side linkage rod 11, a second groove cam 17 of the guide 14, and third groove cams 19 of the levers 12, and by operation of the drive-side rod 13, the moveable pin 18 moves within the respective groove cams 16, 17, 19, causing the levers 12 to rotate, the driven-side linkage rod 13 to be driven in a direction opposite to the drive-side linkage rod 11, and a driven-side arc electrode 5 to be driven in a direction opposite to a drive-side arc electrode 4.

Abstract: TA gas cooler for a medium voltage switchgear assembly with a gas compartment, having a housing with a hollow body for accommodating the heated gas, which flows through the medium voltage switchgear assembly and is heated by at least one heat-generating current conductor, wherein the hollow body of the housing is divided at least partly in several parallel hollow bodies, which are shaped as fins.

Abstract: Switchgear includes a duct by which inside portions of a plurality of cable compartments are linked each other; and a gas flow direction restriction device by which high-pressure gas is flowed only in a predetermined direction in the duct when the high-pressure gas is generated at the inside of any of the cable compartments in the plurality of cable compartments; in which the high-pressure gas can be ejected from a predetermined portion of the switchgear to the outside without increasing outer dimensions of the switchgear in accordance with an internal fault in the cable compartments.

Abstract: The present application provides for an acid precursor capsule that includes an acid precursor that is a non-aqueous ester and a polymerized shell that encapsulates the acid precursor. In some embodiments, the acid precursor converts into an associated acid during a hydrolysis period while in contact with water at an elevated temperature. In further embodiments, the associated acid is soluble in water and forms an aqueous acid solution with water. In certain embodiments, the polymerized shell contains the acid precursor and prevents interaction between the acid precursor and water at the elevated temperature until the polymerized shell dissolves in the water during a dissolution period. An acid precursor capsule suspension can include the acid precursor capsule and a suspension fluid.

Abstract: A solid-dielectric switch includes a visible disconnect assembly having an open state and a closed state. A molded housing at least partially encases the visible disconnect assembly. At least a portion of the molded housing forms a molded one-piece wall having an inner surface and an outer surface. An aperture in the molded one-piece wall extends between the inner surface and the outer surface of the wall. A viewing window is disposed in the aperture and molded into the molded wall. The viewing window includes a lens, wherein the viewing window has an outer edge that is embedded within the molded one-piece wall with the outer edge extending into the molded one-piece wall between the inner surface and the outer surface of the molded one-piece wall.

Abstract: An electrical switch includes a tubular housing having a conductor receiving end and an operating end opposite the conductor receiving end. The tubular housing also includes a conductive interface positioned intermediate the conductor receiving end and the operating end. An operating rod extends through the operating end toward the conductor receiving end. The operating rod is moveable between a first position to engage the electrical switch and a second position to disengage the electrical switch. A gelatinous dielectric material is provided within a portion of the tubular housing, and around the operating rod, in the operating end to prevent voltage from the conductive interface from arcing to the operating end. The gelatinous dielectric material is configured to deform to maintain contact with the operating rod in the first position and the second position.

Abstract: A housing for a high voltage electrical switch includes a tubular body having a top portion and a bottom portion opposite the top portion and removable shed sleeves. A first shed sleeve is removably attached to an outside surface of the top portion, such that an interior surface of the first shed sleeve forms a dielectric interface between the outside surface of the top portion and the interior surface of the first shed sleeve. A second shed sleeve is removably attached to an outside surface of the bottom portion, such that an interior surface of the second shed sleeve forms a dielectric interface between the outside surface of the bottom portion and the interior surface of the second shed sleeve. The first and second shed sleeves are stretched over their respective portions of the tubular body and secured via an interference fit.

Abstract: A muffler for enhanced arc protection is described. In the case of an internal arc event in an electrical enclosure, the muffler exhausts arc gas and plasma parallel to the enclosure surface, instead of directly forward where persons may be located. The muffler includes perforated plates and baffle plates in its interior space. The perforated plates have offset perforation patterns from one another, and the baffle plates are provided on opposing walls, causing the plasma and gas to make multiple directional changes. The perforated plates also filter the arc gas and plasma. These directional changes and filtering result in an energy reduction from the exhaust, which provides an increased margin of safety. In addition, the muffler provides an adequate level of ventilation in the enclosure, thus keeping the components cool.

Abstract: A gas circuit breaker includes: a sealed tank filled with insulation gas; a pair of arc contacts that are arranged to face each other in the sealed tank and connectable and disconnectable with each other; a thermal puffer chamber that is provided on an outer circumferential portion of the pair of arc contacts; a mechanical puffer chamber that is provided on an outer circumference of the thermal puffer chamber and constituted by a cylinder formed in a toric shape centering around an axial line of the arc contacts; and a piston that is formed in a toric shape centering around the axial line and accommodated in the cylinder, and configured to move according to connection and disconnection of the arc contacts.

Abstract: Circuit breakers include an arc chamber and an arc chute comprising a plurality of arc plates in the arc chamber. The circuit breakers also include a line conductor assembly with at least one arc runner attached to a line conductor in the arc chamber. The arc runner can extend below but adjacent to a bottom arc plate to thereby guide a respective arc into the arc chute.

Abstract: Circuit breakers are provided including a pressure release valve. The pressure release valve includes a vent portion and barrier portion. The barrier portion is configured to open when exposed to excessive heat generated by an arc and allow gases to escape from the circuit breaker. Related electrical distribution panels and systems are also provided.

Abstract: Equipment protection systems, arc containment devices, and methods of assembling arc containment devices are disclosed. In one example, an electrical isolation structure includes a conductor base, a cover coupled to the conductor base and defining an isolation chamber, a containment shield disposed on the conductor base within the isolation chamber, and a biasing assembly positioned between the cover and the containment shield. The containment shield defines a containment chamber configured to enclose the plurality of electrode assemblies. The containment shield is configured to at least partially contain the arc products within the containment chamber. The biasing assembly is configured to permit the containment shield to move away from the conductor base to thereby define a gap between the conductor base and the containment shield to enable at least some of the arc gases to vent from the containment chamber.

Abstract: A circuit protection device is provided for use with a circuit that includes at least one pair of conductors. The protection device is configured to generate an arc. The protection device includes at least a pair of electrode assemblies electrically coupled to the at least one pair of conductors and a conductor base to support the pair of electrode assemblies. The protection device includes a cover coupled to the conductor base and defining at least one isolation chamber, wherein the electrode assemblies are disposed within the isolation chamber. The protection device includes a containment shield moveably coupled to the cover. The containment shield defines a containment chamber configured to contain charged particles produced by the arc. The containment shield is operative to move relative to the cover in response to a change in pressure produced by the arc within the containment chamber.

Abstract: A circuit breaker includes a housing equipped with a first switchgear region, in which a quenching chamber device and a sliding contact device having movable contacts are located, the contacts lying opposite fixed contacts, and equipped with a second switchgear region, in which a current release assembly consisting of a short-circuit release and an overload release are located. In an embodiment, a continuous ventilation channel is formed within opposing housing walls along the fixed contacts, the channel acting as a first convective air-flow through the circuit breaker in order to dissipate the heat.

Abstract: In order to improve cooling performance of a switch unit or switchgear equipped with the switch unit, the switch unit includes a switch having a movable electrode and a fixed electrode and is casted as one body with a resin, the resin is provided with resin fins, and the thickness of the resin fin is changed so that the resin fin has a thickness sloped in the longitudinal direction of the resin fin.

Abstract: An arc-resistant switchgear enclosure has a vent opening and a vent flap. Normally the vent flap is open to allow air to circulate through the enclosure. However, in the event of an arc fault explosion in the enclosure, the vent flap is forced to close by the explosion. As the vent flap closes, a flexible latch member moves along a keeper and prevents the vent flap from reopening. In some embodiments, the latch member contacts the keeper and props the vent flap open for normal operation.

Abstract: A circuit breaker includes a shielding component having an external portion which defines a space external to the circuit breaker housing and covers a vent in the circuit breaker housing to direct gasses and debris from the vent to an outlet. The external portion also prevents insertion of the circuit breaker into a breaker box closer than the distances defining the space. This can have the advantage of preventing arcing from the breaker contacts to the breaker box. The external portion may also prevent insertion of the circuit breaker into a breaker box such that a vent in the circuit breaker housing is blocked. In some implementations, the shielding component contains an internal portion which extends into the circuit breaker housing and is disposed to impede debris generated by contact arcing, or other debris, from entering the mechanism of the circuit breaker.

Abstract: A debris collection slot or groove formed near the exit of a vent channel in a circuit breaker. Debris is produced during a circuit interruption, causing the debris to travel into the vent channel toward an opening where it exits the circuit breaker. Too much accumulated debris can lead to a ground strike or a cross-phase condition. The debris collection groove, formed near the exit opening of the vent channel, has no significant effect on the internal pressure generated during the circuit interruption. Multiple grooves can be formed near the exit opening for trapping more debris. When the vent channel is bent, the grooves are positioned on the outer curve of the last bend of the vent channel to trap the higher-density debris traveling around the curve.

Abstract: A gas insulated switchgear includes stationary contacts, movable contacts contactable with or uncontactable from the stationary contacts, an insulation case housing the stationary contacts and the movable contacts so as to support the same, the insulation case having a shape of a pipe, flanges disposed at an inner circumferential surface of the insulation case in a circumferential direction, each of the flanges having an annular shape, and a collection groove portion formed at the flanges and collecting metal particles generated during contact or separation operation between the stationary contactors and the movable contactors. Under this configuration, the metal particles can be collected and laid in the collection groove portion provided at the flanges, accordingly, the metal particles cannot be stuck on an insulation member or other components of the insulation case, resulting in obviating occurrence of insulation breakdown within the switchgear and improving reliability of a product.

Abstract: A power switchgear according to the present invention includes a pass-through hole which is formed in a fixed side contact case that is supported by a fixed side insulation supporter to fix and retain the fixed side of a vacuum valve and has a larger inner diameter than an outer diameter of the vacuum valve so that the vacuum valve is capable of horizontally passing through and the fixed side end portion of the vacuum valve is placed by passing through; and a fixed side connection conductor attached to the fixed side contact case and connected to the fixed side end portion of the vacuum valve.

Abstract: A contact bus bar assembly for supplying power to a load, and further pertains to a switching device which can be connected to such a compact bus bar assembly, and to a power distribution system. The bus bar assembly includes at least two electrically conductive tracks which are at least partly covered by an electrically insulating cover. An outer surface of said insulating cover is provided with a plurality of ribs arranged in a region connecting pin terminals. The switching device may additionally comprise a separating element provided with a plurality of second ribs.

Abstract: A multi-segment tank for high voltage gas circuit breakers such as, e.g., 800 kV gas circuit breakers. The tank includes two or more segments. In a three segment embodiment, the tank includes a short or compact center segment fabricated to mount an interrupter device and support the interrupter's operating linkage, while two end segments are connected with flange joints to surround the remainder of the interrupting device. Alternatively, a tank is provided that is constructed in two segments.

Abstract: A breaking device with an arc breaking shield comprising at least one stationary contact collaborating with a movable contact supported by a contact-holder arm and an actuating device of the movable contact in a casing. A movable arc breaking shield is commanded in movement to occupy a rest position and a laminating position. The movable breaking shield is connected to the contact-holder arm by an actuating rod in such a way that movement of the contact-holder arm results in movement of the movable breaking shield, the actuating rod being respectively connected to the movable breaking shield and to the contact-holder arm by a second and third pivot-pin.

Abstract: An electrical switch includes a tubular housing that includes an interface positioned intermediate the conductor receiving end and the operating end. An operating rod extends through the housing. A fixed contact is electrically coupled to the operating end. A moveable contact is electrically coupled to the interface and the operating rod, wherein the moveable contact is moveable between a first position contacting the fixed contact and a second position separated from the fixed contact. A diaphragm is positioned in the tubular housing between the interface and the operating end and includes a first tubular portion and a second tubular portion. Movement of the operating rod from the first position to the second position causes the second tubular portion to move relative to the first tubular portion, thus deforming the shoulder portion.

Abstract: A gas insulated switchgear includes: a center conductor that is arranged to extend horizontally in a tank; a cylindrical member that is arranged in the tank to surround a center conductor, and formed by curving a metal plate-like member into a cylindrical shape and then joining circumferentially opposed both ends of the plate-like member by welding to form a welding portion, the welding portion being located on a lower side of the cylindrical member; and a current transformer for instruments, through which the cylindrical member is inserted, the current transformer being supported by the cylindrical member, and being arranged to surround the center conductor. The welding portion includes a metal spacer sandwiched between the circumferentially opposed both ends of the plate-like member, and the spacer and the ends are welded to each other.

Abstract: A protective door having push switches, access to racking unit and viewing windows is assembled with the electrical device such that the protective door encloses the electrical device with a flame proof sealing. The push switches and cutout to access racking unit are made aligned with the electrical device such that the switches of the electrical device are actuated through the push switches, racking in and out the device is possible through the cutout to access racking unit and it allows reading the rating plate, display of the electrical device through the viewing windows in the protective door even if the protective door is closed. The push switch has a push rod and a spring loaded push button assembled inside a cylinder and the push button is clamped from the front of the protective door. The push switches are arranged such that a reset switch contact with the position reset switch of the electrical device, push switches to respectively switch ON and Switch OFF the electrical device.

Abstract: In a gas-insulated power apparatus in which contiguous vessels 11, 12 (GIBC1, GIBC2) are coupled by way of flanges 111, 121 of respectives thereof, and power conductors 112, 122 (GIBC5) insulated from the vessels by an insulating gas 13 are included in the vessels, by squeezing the flange 111 of the vessel on one side to be coupled by a pressing member 14 screwed to the flange 121 of the vessel on other side and the flange 121 of the vessel on other side, positions of the vessel on one side and the vessel on other side coupled as described above relative to each other can be shifted in a peripheral direction of the flange, and therefore, even when a direction of leading out a gas-insulated bus or the like becomes various depending on products, various directions can be dealt with out depending only on design of respective product specifications.

Abstract: An electrical enclosure includes a mechanism for moving and/or extinguishing an arc fault occurring in a first compartment of the electrical enclosure. The mechanism is positioned adjacent to a busbar in a second compartment of the electrical enclosure. In the case of a first arc fault occurring in the first compartment, an explosion occurs which results in a pressure wave. The pressure wave causes the mechanism to move into the second compartment and make electrical contact with the busbar, which causes a short and/or a second arc fault in the second compartment, thereby extinguishing the first arc fault in the first compartment.

Abstract: A pole assembly for a three phase breaker includes a center pole and a pair of outer poles positioned on opposed sides of the center pole. A pair of brackets are positioned at opposed ends of the pole, and include a center groove and a pair of outer grooves. The center pole is positioned in the center groove. The outer poles are secured in the outer groove in a shipping configuration and an installed configuration. When in the shipping configuration the bushings of all the poles are parallel. When in the installed configuration the bushings of the outer poles are angled away from the bushings of the center pole.

Abstract: An electrical enclosure includes a housing having a first end, an opposite second end, and a plurality of sides disposed therebetween to define an internal volume; an electrical busway having a plurality of electrical bus members; a plurality of phase-to-phase arc length limiters, each of the phase-to-phase arc length limiters being electrically connected to a corresponding one of the electrical bus members, each of the phase-to-phase arc length limiters having a first edge and a second edge, the first edge establishing a first gap to an adjacent one of the phase-to-phase arc length limiters; and a phase-to-ground arc length limiter electrically connected to the housing, the phase-to-ground arc length limiter having a number of members structured to attach an arc, each of the number of members having a number of arc attachment portions establishing a second gap to the second edge of the phase-to-phase arc length limiters.

Abstract: Embodiments provide circuit breakers with stops adapted to prevent a lug screw from falling out of circuit breaker and/or to prevent the lug screw from blocking a wire receiver of circuit breaker lug body. In one aspect, a circuit breaker is provided having a circuit breaker housing; a lug assembly retained in the circuit breaker housing, the lug assembly including a threaded screw hole; a lug screw having driving end and a threaded shaft inserted in the threaded screw hole; and a back-out stop adapted to contact the driving end and limit an extent of backward movement of the lug screw out of the threaded screw hole. Other aspects are provided.

Abstract: The disclosure relates to an insulator for positioning an electrical conductor in a gas chamber in a housing of a gas-insulated switchgear assembly, which comprises an electrically insulating disc-shaped carrier element with at least one cutout for passing through an electrical conductor. At least one notch for accommodating a clamp element is arranged on the outer circumference of the carrier element at least one point.

Abstract: A gas-insulated switchgear apparatus includes a center conductor 2, a current transformer 4 surrounding the center conductor 2, an electric field shield 5, and a metallic vessel 1. The electric field shield 5 is located between the center conductor 2 and the current transformer 4 and surrounds the center conductor 2. The current transformer 4 and the electric field shield 5 constitute a tubular part that outputs a signal representing an electric physical quantity. The metallic vessel 1 is filled with an insulating gas 19. The tubular part has an opening 6 formed therein. In a posture in which the center axis of the tubular part about which the tubular part surrounds the center conductor 2 is substantially horizontal, the opening 6 is located in a surface of the tubular part, which surface is included in a lower portion of the tubular part and faces the center conductor 2.

Abstract: A vacuum cartridge (1) is manufactured with a dielectric coating (22) made from elastomer directly on the enclosure of the chamber (2) of the cartridge (1). To prevent the elastomer from infiltrating into the chamber (2) of the cartridge and/or its enclosure from breaking, cover-plates (26) performing mechanical protection and dielectric deflection cover the covers (61, 62) of the chamber (2) and their braze (8) with the ceramic tube (4).

Abstract: A gas circuit breaker includes a grounded tank corresponding to each one of the plurality of phases, a bushing, an upper housing, and a lower housing, those mounted on a base that is supported by a frame. The grounded tank and the upper housing are located on a plane. The lower housing is connected to the grounded tank with a connecting unit such that the lower housing can be moved from a first position for operation lower than the plane to a second position for transportation substantially on the plane.

Abstract: This invention relates to a circuit breaker (1) for high or medium voltages, of the type having a drive bar (70) coupled to a drive member, and a circuit-breaking chamber (2) facing it and having two contacts (3, 4), each contact (3, 4) including a main contact (30, 40 respectively) and an arcing contact (31, 41 respectively), with one of the two contacts (3) being fixed to a blast or extinguishing nozzle (32). According to the invention, the second contact (4) and the drive bar (70) are joined together by coupling means (6) in such a way that they move together in translation in the same direction, the transmission means (5) being disposed on the side (21) of the chamber (2) that is adjacent to the drive bar (70), and are adapted to transmit the motion of the driven second contact (4) to the first contact (3).

Abstract: A gas-insulated switchgear includes an electric conductor that is housed in a vessel that is sealed and filled with insulating gas, a current transformer that is housed in the vessel, which includes a coil wound around the electric conductor, an electric-field relaxing shield that is arranged in the vessel at a radially inward position relative to an inner side of the coil, and a dielectric insulating member that is arranged on an end portion of the electric-field relaxing shield.

Abstract: A switching installation including a gas-filled enclosure, an input conductor, an actuator and a short-circuit device. The actuator is arranged to actuate the short-circuit device upon the occurrence of a first arc in the enclosure. The short-circuit device creates, upon being actuated, a short-circuit through the solid insulation between the input conductor and the enclosure or a separate ground point. The actuator can be arranged to react on an increase in pressure in the enclosure upon the occurrence of the first arc. The gas can be air or SF6. The short-circuit device can create, upon being actuated, the short-circuit through a section of a solid cable insulation isolating the input conductor from the enclosure.

Abstract: A circuit breaker is provided having three horizontal circuit breakers coupled together with a base housing. Each of the horizontal circuit breakers comprising a tank secured in the housing, first and second current transformers extending from the tank and exit and entrance insulators extending from the first and second current transformers. The housing is mountable on a support frame. To facilitate shipping and field assembly, the circuit breaker includes an control panel moveably coupled to the housing.

Abstract: A multiphase current interrupter is provided for interrupting a phase current between two contacts in an electrical phase. The current interrupter includes a first ablative chamber disposed around contacts for a first electrical phase. The first chamber has an ablative material thereon that causes a shock wave when an electrical arc is generated in an arc zone for the first electrical phase during a separation of the contacts therein. The current interrupter further includes at least a second ablative chamber disposed around contacts for at least a second electrical phase. The second chamber has an ablative material thereon that causes a shock wave when an electrical arc is generated in an arc zone for the second electrical phase during a separation of the contacts therein. An interconnecting structure provides fluid communication between the first ablative chamber and the second ablative chamber. The interconnecting structure is adapted to dissipate a shock wave generated in any of the ablative chambers.

Abstract: A hermetically sealed relay is provided having two circuits therein.

Abstract: A particle trap has a cover cap which dielectrically shields a shielding area by way of a shielding surface. The shielding surface has a concave curvature. Transversely to the concave curvature, the shielding surface has surface regions which are inclined transversely to the concave curvature in the region of a trough of the concave curvature.

Abstract: An arc member is provided for an electrical switching apparatus. The electrical switching apparatus includes an operating mechanism for opening and closing separable contacts, and an arc chute disposed proximate the separable contacts to attract an arc generated thereby. The separable contacts include a stationary contact and a movable contact. The stationary contact has an edge, which is disposed in a plane. The arc member includes an arc element disposed between the stationary contact and the arc chute. The arc element has first and second portions and first and second arc attractors. The first arc attractor extends outwardly from the first portion toward the plane of the edge of the stationary contact to draw the arc from the separable contacts to the arc member. The second arc attractors, which are disposed on the second portion of the arc element, direct the arc into the arc chute.

Abstract: A switch unit comprising a circuit breaker and a disconnector disposed in one plane and fixed to a metal casing. Common drive means comprise: a single insulating drive bar adapted to move in a straight line in the same plane as the plane of straight line movement of the movable contacts of the circuit breaker and disconnector; and at least one mechanical assembly mounted in the metal casing, at least part of the mechanical assembly being driven by the single insulating drive rod while permitting non-simultaneous straight-line movement of the two movable contacts.