Current breaking device with solid-state switch and built-in protective circuit breaker

Claim 1

A low voltage current breaking device with a modular case having a front face, two large parallel side faces, and two small side faces, each presenting a shoulder to house a pair of power terminals and at least one control terminal, said shoulders being located opposite the front face towards the rear part of the case, within said case being housed and connected in series a solid-state switch and a pair of separble contacts actuated by a mechanism having an operating toggle, located on said front face, and a trip unit causing the contacts to separate when a fault occurs thus protecting the solid-state switch, said case including in its rear part a first housing confined by an external metal plate forming the base of the case and an intermediate separating partition of a second housing, only the solid-state switch being located in said first housing in thermal contact with the metal plate, said separable contacts, mechanism and trip unit being located in the second housing, whereby said first housing is thermally isolated from said second housing; said breaking device further comprising a shunting circuit of the solid state switch including an arc guiding horn located in proximity to one of said pair of contacts, said horn being shaped so that as soon as the contacts separate, the distance between the horn and the other of said pair of contacts is smaller than the distance separating the pair of contacts, whereby an arc drawn when the pair of contacts separate is transferred to said shunting circuit avoiding flashover between said pair of contacts and protecting the solid state switch from a fault current.