Disclosed in the present invention is an electric switching apparatus, comprising a drawer apparatus, an electric connection apparatus, a driving mechanism, and a locking mechanism. The driving mechanism drives a breaker body to move; the relative positions of the breaker body and the drawer apparatus comprise: a separate position, a trial position, a connected but not clamped position, and a connected and clamped position. A busbar of the breaker body at the separate position is separated from the electric connection apparatus, and the breaker body cannot be switched on. The busbar of the breaker body at the trial position is separated from the electric connection apparatus, and the breaker body can be switched on. The busbar of the breaker body at the connected but not clamped position is in touch with the electric connection apparatus, the electric connection apparatus does not clamp the busbar, and the breaker body cannot be switched on. The busbar of the breaker body at the connected and clamped position is in touch with the electric connection apparatus, the electric connection apparatus clamps the busbar, and the breaker body can be switched on.

A bushing for a metal clad medium voltage switchgear includes a hollow body. The body is made of polyamide. A first end of the body connects to a compartment of the medium voltage switchgear. A second end of the body connects to a T-off and pin. A body portion extends from the first end of the body to the second end of the body. The body portion is circular shaped about an axis extending from the first end of the body to the second end of the body.

A contact arm assembly includes a contact arm defining a central axis and having a first end configured for electrical connection with a pole of a circuit breaker and a second end having a distal end defining a shoulder and an engagement that protrudes from the contact arm proximal to the shoulder. A plurality of contact fingers are mounted circumferentially on the second end of the contact arm and configured to electrically engage a primary circuit contact. Each contact finger has a body with a depression that receives the engagement for electrical contact.

A medium-voltage switchgear system includes a three-phase circuit breaker having first, second and third single-phase vacuum interrupters connected between respective first, second and third single-phase inputs and first, second and third single-phase outputs. Magnetic actuators are connected to first, second and third single-phase vacuum interrupters, which are configured to receive an interrupt signal and in response, actuate the respective vacuum interrupter connected thereto into an open circuit condition. A controller circuit is connected to each of the first, second and third magnetic actuators and generates an interrupt signal in response to a detected single-phase overcurrent or fault on a single-phase circuit and interrupt that single-phase circuit on which the single-phase overcurrent or fault occurred and maintain power on the remaining two single-phase circuits over which a single-phase overcurrent or fault was not detected.

A system for transferring heat generated in an electrical enclosure includes run-in buses, a thermally conductive plate, and at least one contact assembly secured to the plate. Each pair of adjacent run-in buses is separated by a space. The plate has at least one opening extending therethrough, and the plate receives the run-in buses through the at least one opening. The at least one contact assembly has spaced apart fingers that partially cover the at least one opening of the plate, and adjacent fingers define a slot. Each of the fingers is located in a space between adjacent run-in buses, and each of the run-in buses is located in a slot when the fingers are located in the spaces between adjacent run-in buses. The run-in buses and contact assembly fingers are oriented in an interleaved pattern.

A motor control center includes an enclosure comprising an isolation switch, a main contactor device, and a ground switch device. The isolation switch is selectively manually operable between a connected state and a disconnected state. In the connected state the isolation switch is adapted to conduct electrical power from an associated power source to the main contactor device and wherein the isolation switch in the disconnected state interrupts conduction of electrical power from the associated power source to the main contactor device. The main contactor device is selectively operable between a conductive state and a non-conductive state, wherein the main contactor device is adapted to electrically connect the isolation switch to the ground switch device and to an associated electrical load when the main contactor device is in its conductive state and wherein the main contactor device disconnects said isolation switch from the ground switch device and the associated electrical load when the main contactor device is in its non-conductive state. The ground switch device is manually operable from an open, ungrounded state in which the main contactor device is electrically disconnected from a ground path to a closed, grounded state in which the main contactor device is electrically connected to the ground path. The motor control center further includes a first interlock device operably connected between the isolation switch and the ground switch device, wherein the first interlock device prevents movement of the isolation switch from the disconnected state to the connected state when the ground switch device is in the grounded state.

A motor control center includes an enclosure comprising an isolation switch, a main contactor device, and a ground switch device. The isolation switch is selectively manually operable between a connected state and a disconnected state. In the connected state the isolation switch is adapted to conduct electrical power from an associated power source to the main contactor device and wherein the isolation switch in the disconnected state interrupts conduction of electrical power from the associated power source to the main contactor device. The main contactor device is selectively operable between a conductive state and a non-conductive state, wherein the main contactor device is adapted to electrically connect the isolation switch to the ground switch device and to an associated electrical load when the main contactor device is in its conductive state and wherein the main contactor device disconnects said isolation switch from the ground switch device and the associated electrical load when the main contactor device is in its non-conductive state. The ground switch device is manually operable from an open, ungrounded state in which the main contactor device is electrically disconnected from a ground path to a closed, grounded state in which the main contactor device is electrically connected to the ground path. The motor control center further includes a first interlock device operably connected between the isolation switch and the ground switch device, wherein the first interlock device prevents movement of the isolation switch from the disconnected state to the connected state when the ground switch device is in the grounded state.

Embodiments of a plug-in unit for an electrical enclosure are disclosed. The plug-in unit includes at least one stab configured to engage a bus, a stab shaft coupled with a base of the at least one stab, and a stab translation mechanism configured to translate the stab shaft such that the at least one stab translates from a retracted position to an extended position.

A contact arm assembly includes a contact arm defining a central axis and having a first end configured for electrical connection with a pole of a circuit breaker and a second end having a distal end defining a shoulder and an engagement that protrudes from the contact arm proximal to the shoulder. A plurality of contact fingers are mounted circumferentially on the second end of the contact arm and configured to electrically engage a primary circuit contact. Each contact finger has a body with a depression that receives the engagement for electrical contact.

A medium-voltage switchgear system includes a three-phase circuit breaker having first, second and third single-phase vacuum interrupters connected between respective first, second and third single-phase inputs and first, second and third single-phase outputs. Magnetic actuators are connected to first, second and third single-phase vacuum interrupters, which are configured to receive an interrupt signal and in response, actuate the respective vacuum interrupter connected thereto into an open circuit condition. A controller circuit is connected to each of the first, second and third magnetic actuators and generates an interrupt signal in response to a detected single-phase overcurrent or fault on a single-phase circuit and interrupt that single-phase circuit on which the single-phase overcurrent or fault occurred and maintain power on the remaining two single-phase circuits over which a single-phase overcurrent or fault was not detected.