A unitary molded housing for a multipole high capacity circuit breaker wherein the housing may receive and support modules of different current carrying and interrupting capacity. The molded housing has vertical side walls and parallel vertical integral interphase barriers as well as a back wall and top wall. Disconnect contact bars are mounted through the back wall and support and are connected to circuit breaker contact structures at the front side of the back wall. Recesses which receive the arc extinguisher structure are formed by adjacent vertical walls and the top wall. The interior of the top wall forms a baffle or guide on which arc gases vented from the arc extinguisher impinge and are guided to the vertical walls and the spaces between the said walls and the arc extinguishers.

The present invention provides an interior assembly for an electrical distribution device having a fuse for each phase in a circuit. The interior assembly includes a plurality of modules having an operating mechanism for opening and closing a switch contact. The switch contact is connected to each fuse and phase of the circuit. Each module has a housing and a mechanism for demountably securing one of the modules to at least one adjacent module. The securing mechanism is manually operated and integrally formed with the housing of each module. The present invention also provides a method of assembling the interior assembly of an electrical distribution device having a fuse for each phase in a circuit. The step of the method includes manually and demountably affixing a plurality of modules to one another without discrete fasteners. The plurality of modules have an operating mechanism for opening and closing a switch contact. The switch contact is connected to each fuse and phase of the circuit.

A vacuum switching apparatus includes at least two switching vessels arranged side by side and operable by an actuator device. Insulating partitions are situated between the switching vessels and are formed by insulator members which each enclose a switching vessel and are arranged side by side with a spacing therebetween. One application of the invention is in three-phase vacuum contractors for voltages of up to about 10 kV.

The following specification describes a fusible switch assembly having a thermoplastic base supporting a plurality of pivotal knife blades. A one piece thermoplastic arc suppressor housing common to a plurality of phases is also described together with arc suppressor plates snap fit in the housing and a common one piece thermoplastic rotor for moving the blades. The rotor is retained by engagement with the knife blades and walls of the base.

A three-pole disconnect switch includes a crossbar which is rotatably mounted to a housing and pivots three movable contact blades between opened and closed positions. Each movable contact blade is removably mounted to the cross-bar and makes slidable electric contact with a connector. When in its closed position, each movable contact blade makes electrical connection with a stationary line contact. Modular arc chutes are slidably received in mating cavities formed in the housing above each set of contacts and a pair of auxiliary contact cartridges are received in chambers formed in the housing between the main contacts. A trip mechanism is mounted to the side of the housing and couples one end of the crossbar to a manually operated handle.