The electrical switch includes a first and a second fixed contact, and a movable knife contact including at least one longitudinal pair of blades being flexibly connected to each other, wherein the blades form, in a switching event, contact with contact portions of the first and/or the second fixed contact. Opposite surfaces of the contact portions of the first and the second fixed contact include a roughened area and the inner surface of each blade includes a protruded area or opposite surfaces of the contact portions of the first and the second fixed contact include a protruded area and the inner surface of each blade includes a roughened area.

Switching devices having a contact point, and an arc extinguishing chamber are used to blow switch arcs. The arc extinguishing chamber may have an exit opening through which plasma, generated inside the switching device by a switch arc developing when the contact point opens, exits out of the switching device. Inside the extinguish chamber a first arc guide plate may be provided that extends from the contact point toward the exit opening and which guides and stretches the switch arc. The switch arc may be initially stretched beyond the dimensions of the exit opening by the first arc guide plate and then the stretching may be reduced to be within the dimensions of the exit opening by an arc guide pin projecting from the first arc guide plate.

An electric fuse box or junction box assembly has a high voltage electric line cutter assembly inside an electric fuse box or junction box. The assembly has a box housing for connecting a plurality of electrical lines or connections to a power source. The housing has a pair of mounting stanchions for affixing the high voltage electric line cutter assembly with an electric current carrying busbar having a pair of stub ends. Each stub end of the busbar for carrying electric current from the power source to the plurality of electrical lines is secured to one of the mounting stanchions. Each mounting stanchion has an attachment platform for attaching and supporting the stub end of the busbar and an underlying chamber below the attachment platform for receiving exhaust gases generated when the high voltage electric line cutter assembly is activated.

A power semiconductor module including a housing within which lies at least one semiconductor switching element. The housing includes a vent aperture that is selectively openable and closeable by a cooperating vent cover. The vent cover is held in an open position during normal operation of the power semiconductor module to open the vent aperture and provide ventilation for the or each semiconductor switching element within the housing. The vent cover is urged into a closed position by an increase in pressure within the housing resulting from an explosive event inside the housing to close the vent aperture and inhibit the escape of explosion gases and/or debris from the housing via the vent aperture

To provide an electric circuit breaker device that can be downsized while maintaining strength. An igniter 20, a bar-shaped projectile 40, a conductor piece 50, and an insulating space 61 are provided inside a resin housing 10. A cylinder 30 is disposed between the bar-shaped projectile 40 and an inner wall surface of the housing 10, and further, a reinforcing frame 70 is disposed in the housing 10 on the outer side. A discharge path for combustion products generated by actuation of the igniter 20 is provided between the insulating space 61 and a second end 12 of the housing.

An electromagnetic relay includes a casing having a housing space open to an external to the casing through an opening. A base is joined to the casing to close the opening. A coil, a pair of fixed contact elements and a pair of movable contact elements are housed in the housing space. A vent hole set to a dimension making it possible to extinguish flame passing therethrough is formed in a portion where the casing and the base are joined together.

A single- or multi-pole power circuit-breaker, comprises main contacts, overload- and/or short-circuit current-actuated tripping means, an actuating mechanism for the main contacts, an arc chute and a pressure trip unit having a return element and an actuating element responsive to an overpressure in the arc chute. The tripping of the power circuit-breaker by a trip mechanism is executable both by the tripping means and the pressure trip unit. The pressure trip unit is arranged immediately adjacently to both the arc chute and a main busbar. A tripping lug mechanically engages with the trip mechanism such that an overpressure in the arc chute is transmitted virtually instantaneously to the pressure chamber. The actuating element is configured to switch over directly from a home position to a tripping position, against the force of the return element, in a case of overshoot of a pressure threshold value set by the return element.

A low-voltage multipolar circuit breaker includes a moulded housing including a main body that is divided into interior compartments, each associated with one pole of the circuit breaker, and a cover that is mounted on the main body covering a main face of the body. The circuit breaker includes, for each pole, electrical contacts that can be separated by a device of a switching mechanism and an arc-extinguishing chamber. For at least two of the poles, the main face includes an additional aperture, each placed directly above the spark guard of the corresponding pole and placing the arc-extinguishing chamber of this pole in communication with the interior volume delimited by the cover and the main face, and the cover is attached to the main body while leaving a peripheral opening between the cover and the main body, placing the interior volume in communication with the exterior of the housing.

An electric line cutter device for high voltage busbars has a two-part housing, a piston, an igniter and a busbar. The upper housing includes a cylinder, cuboid or prism chamber. The lower housing also includes a cylinder, cuboid or prism chamber. The piston is contained inside one of either the upper housing chamber or the lower housing chamber. Upon igniting the igniter, the piston breaks a portion of the busbar moving the piston and the portion of the busbar into the opposite chamber thereby stopping the electric current flow. The piston is at least partially formed as an insulator to prevent electric discharge. The piston design together with chamber design includes integrated squeeze areas and blow channels for the appearing arc. A channel system outside or from inside the piston allow the pyro gases to push the arc plasma into a filter system to cool down the gases.

The present invention relates to an arc ventilation system of a multi-stage distributing board, and more particularly, to an arc ventilation system of a multi-stage distributing board having an arc ventilation detour path, capable of preventing an arc generated in a lower compartment from damaging an upper compartment. The arc ventilation system of a multi-stage distributing board according to an embodiment of the present invention includes a first compartment provided at a first stage of an enclosure of the distributing board, a second compartment provided at a second stage located above the first stage, a side arc ventilation compartment provided at one side of the first compartment and the second compartment, and a middle arc induction compartment provided between the first compartment and the second compartment and communicating with the side arc ventilation compartment.