A keyboard device includes plural key structures, a switch circuit board, an elastic cover and a seal element. The switch circuit board includes a hollow region. The elastic cover is disposed on the switch circuit board. The hollow region is covered by the elastic cover, so that a foreign liquid is prevented from entering the switch circuit board. The seal element is disposed on sidewalls of the switch circuit board. Consequently, a sealed region is formed between the switch circuit board and the elastic cover. When the inner gas within the switch circuit board is changed, the elastic cover is subjected to expansion or contraction. Consequently, the switch circuit board is not subjected to deformation in response to the volume change of the inner gas.

A keyboard device includes plural key structures, a switch circuit board, an elastic cover and a seal element. The switch circuit board includes a hollow region. The elastic cover is disposed on the switch circuit board. The hollow region is covered by the elastic cover, so that a foreign liquid is prevented from entering the switch circuit board. The seal element is disposed on sidewalls of the switch circuit board. Consequently, a sealed region is formed between the switch circuit board and the elastic cover. When the inner gas within the switch circuit board is changed, the elastic cover is subjected to expansion or contraction. Consequently, the switch circuit board is not subjected to deformation in response to the volume change of the inner gas.

Circuit interrupting devices, power distribution switchgear assemblies, and pole units for power distribution are provided. A circuit interrupting device includes a solid insulation housing, a disconnect, a window, and an insulating fluid. The solid insulation housing defines a first external opening and a first cavity extending into the solid insulation housing from the first external opening. The disconnect has a moving contact in selective engagement with a stationary contact in the first cavity. The window is secured to the solid insulation housing at the first external opening. The insulating fluid is disposed within the first cavity. The window, the solid insulation housing, or a combination thereof is configured to form a trap region that is in fluid communication with the first cavity and is configured to trap air bubbles in the insulating fluid.