A shutter interlock device for an electrical enclosure includes a shutter link defining a lock slot, an actuating member rotatably coupled to the electrical enclosure, and a sliding link. The sliding link includes a first end coupled to the actuating member, a second end opposite the first end, and a pin coupled to the second end, where a rotation of the actuating member causes the pin to selectively disengage the lock slot.

A passive arc control system for a motor control center 60 includes an arc attenuating box having sides separating adjacent vertical bus bar phases 54, providing a physical barrier to arc flash energy. The box is open at its top and bottom forming a chimney 55. A shutter assembly for each box includes an insulator cap 62 on a free end of the bus bar and an independently moveable, box-shaped shutter 64 that slides along the bus bar away from the insulator cap, when a device is connected to the bus bar. The shutter has an opening 65 through which the bus bar passes when the device is connected to the bus bar and an opening 55′ aligned with the box's chimney. The arc control system provides a high degree of arc protection for personnel working around open motor control centers and is highly modular and easy to construct.

A passive arc control system for a motor control center 60 includes an arc attenuating box having sides separating adjacent vertical bus bar phases 54, providing a physical barrier to arc flash energy. The box is open at its top and bottom forming a chimney 55. A shutter assembly for each box includes an insulator cap 62 on a free end of the bus bar and an independently moveable, box-shaped shutter 64 that slides along the bus bar away from the insulator cap, when a device is connected to the bus bar. The shutter has an opening 65 through which the bus bar passes when the device is connected to the bus bar and an opening 55′ aligned with the box's chimney. The arc control system provides a high degree of arc protection for personnel working around open motor control centers and is highly modular and easy to construct.

A shielding arrangement can be provided for a piece of high voltage equipment spaced from a neighboring object. The piece of high voltage equipment has a first electric potential and the neighboring object has a second electric potential. The shielding arrangement includes a resistor, a shield element for connection to the high voltage equipment via the resistor, and a capacitor connected in parallel with the resistor. A resistance of the resistor and a capacitance of the capacitor together define a time constant in a range of 10 μs-50 ms.

A shielding arrangement can be provided for a piece of high voltage equipment spaced from a neighboring object. The piece of high voltage equipment has a first electric potential and the neighboring object has a second electric potential. The shielding arrangement includes a resistor, a shield element for connection to the high voltage equipment via the resistor, and a capacitor connected in parallel with the resistor. A resistance of the resistor and a capacitance of the capacitor together define a time constant in a range of 10 μs-50 ms.

An interlock structure of a bypass transfer switching device is proposed. When supply power is bypassed through a bypass switch, the interlock structure may prevent manual switching on an automatic transfer switch, and allow the automatic transfer switch to be input into a switchboard when power input directions of the bypass switch and the automatic transfer switch match with each other. The interlock structure includes: the automatic transfer switch having a lever input portion for manual switching of a normal supply and an alternative supply; the bypass switch configured to bypass electric power of the normal supply or the alternative supply supplied to a load side through the automatic transfer switch; and an interlock device configured to automatically close the lever input portion when the bypass lever is operated.

An interlock structure of a bypass transfer switching device is proposed. When supply power is bypassed through a bypass switch, the interlock structure may prevent manual switching on an automatic transfer switch, and allow the automatic transfer switch to be input into a switchboard when power input directions of the bypass switch and the automatic transfer switch match with each other. The interlock structure includes: the automatic transfer switch having a lever input portion for manual switching of a normal supply and an alternative supply; the bypass switch configured to bypass electric power of the normal supply or the alternative supply supplied to a load side through the automatic transfer switch; and an interlock device configured to automatically close the lever input portion when the bypass lever is operated.

An interlock structure of a bypass transfer switching device is proposed. When supply power is bypassed through a bypass switch, a lever input portion is closed to prevent manual switching of an automatic transfer switch, and when the automatic transfer switch is drawn from a switchboard, the closed lever input portion is automatically opened. The interlock structure includes: the automatic transfer switch having the lever input portion of a through hole shape for the manual switching of a normal supply and an alternative supply; the bypass switch configured to bypass electric power of the normal supply or the alternative supply supplied to a load side through the automatic transfer switch, the bypass switch including a bypass lever capable of manually changing a bypass circuit; and an interlock device configured to automatically close the lever input portion when the bypass lever is operated.

An interlock structure of a bypass transfer switching device is proposed. When supply power is bypassed through a bypass switch, a lever input portion is closed to prevent manual switching of an automatic transfer switch, and when the automatic transfer switch is drawn from a switchboard, the closed lever input portion is automatically opened. The interlock structure includes: the automatic transfer switch having the lever input portion of a through hole shape for the manual switching of a normal supply and an alternative supply; the bypass switch configured to bypass electric power of the normal supply or the alternative supply supplied to a load side through the automatic transfer switch, the bypass switch including a bypass lever capable of manually changing a bypass circuit; and an interlock device configured to automatically close the lever input portion when the bypass lever is operated.

An elongated busbar board (1) for connection of devices (11) to a power busbar system comprises a front side touch protection cover plate (2) consisting of touch protection cover plate segments (2-i) made of an electrically insulating material and having feedthrough openings (7) for electrical connection contacts (13A) of devices (11) to be connected to the elongated busbar board. The touch protection cover plate is adapted to cover power busbars (6) made of an electrically conductive material having contact openings (5) lying directly beneath the feedthrough openings and comprises a touch protection base plate (3) connected to the touch protection cover plate and consisting of touch protection base plate segments (3-i) made of the electrically insulating material and adapted to cover the power busbars enclosed by the elongated busbar board from behind, wherein a thermal expansion difference caused by different thermal expansion coefficients of the electrically insulating material and of the electrically conductive material is compensated.