Abstract: In an enclosed switchboard having a vertical bus bar supported by an insulating cover and unit chambers situated in front of the vertical bar and tiered one above the other for accommodating unit devices, each unit device having a stab-type connector including a tongue-shaped contact for establishing electrical contact with the vertical bus bar, the insulating cover includes a vertically extending channeled portion, the vertical bus bar includes a web in flat engagement with the front face of the bed of the channeled portion, a vertically extending protrusion protruding from the web forwardly, and a flange extending from one of the edges of the web and being in flat engagement with the inner face of one of the side walls of the channeled portion, the protrusion being positioned close to the flange so that as the contact moves sidewardly away from the protrusion it is brought into contact with the flange.

Abstract: A handle operating mechanism adapted for use with an electric circuit breaker including a manually operable handle member, an operating axle having an elongated hole formed therein, a cylindrical member having a guide hole of predetermined formation provided therein, and a pin engaged with each of the above members. In a certain position, when the handle is moved in the axial direction of the operating axle, a hole is formed on the handle for cooperation with a locking member.

Abstract: In a motor control center of the present invention, a plurality of units are mounted on a frame. Each of these units has an appliance mounting plate with two walls which extend transversely from the floor plate in stepped form. A first group of electrical appliances which requires relatively frequent maintenance and inspection among the electrical appliances to be mounted in the unit is mounted at the front sides of said two walls and a second group of electrical appliances which requires less frequent maintenance and inspection is mounted on the back side of the wall nearest the front.

Abstract: In an enclosed switchboard, each of side plates is provided, along both edges thereof, with vertically extending ribs having a U-shaped cross section protruding toward the confronting side plate. Connecting members for connecting the side plates are formed to fit in U-shaped cutaway portions provided at the upper and the lower ends of the ribs. A vertically extending opening is provided in the side plate to permit ventilation and wirings through the side plate.